Communication terminal, communication system, and method of sharing data

ABSTRACT

A communication terminal comprising circuitry to: receive selection of screen data, from among one or more items of screen data, as sharing target data to be shared with other communication terminal, each screen data to be used for generating a display screen and having been generated at the communication terminal; and share the sharing target data with the other communication terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35U.S.C. § 119(a) to Japanese Patent Application No. 2019-173759, filed onSep. 25, 2019, in the Japan Patent Office, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to a communication terminal, acommunication system, and a method of sharing data.

Discussion of the Background Art

Communication systems are now in widespread use, which allowscommunication terminals at remote locations to communicate through acommunication network such as the Internet. Examples of thecommunication systems include a conference system that performs a videoconference. In general, a communication terminal operated by one partyin the video conference transmits image data being held or displayed atthe communication terminal to other communication terminal operated byother party through a communication network, to cause the image data andaudio data to be shared between the communication terminals. Thisenables to carry out a video conference between remote locations, in astate close to an actual conference.

Furthermore, in recent years, communication terminals such as electronicwhiteboards are widely used in companies, educational institutions, orgovernment institutions. The electronic whiteboards display an image ona display and allows users to draw stroke images such as text, numbers,figures, or the like on the image. The communication terminalelectronically converts content drawn through a user operation oftouching and moving an electronic pen or the user's hand on a surface ofa display of the communication terminal, to generate stroke data such ascoordinate data. The stroke image is rendered based on the stroke data.When a stroke image is drawn on one communication terminal, stroke datafor reproducing the stroke image is transmitted to the othercommunication terminal through a communication network. The othercommunication terminal displays the same stroke image based on thereceived stroke data.

The techniques described above enable one communication terminal totransmit stroke data for generating a stroke image as well as image dataof documents such as documents (e.g., slides for presentation) that arestored in the communication terminal or that are currently beingdisplayed at the communication terminal through a communication network.The other communication terminal on the receiving side displays an imagesuch as an image of materials or a screen background as well as thestroke image.

SUMMARY

Example embodiments include a communication terminal including circuitryto: receive selection of screen data, from among one or more items ofscreen data, as sharing target data to be shared with othercommunication terminal, each screen data to be used for generating adisplay screen and having been generated at the communication terminal;and share the sharing target data with the other communication terminal.

Example embodiments include a communication system including: firstcircuitry, residing on a first communication terminal, to receiveselection of screen data, from among one or more items of screen data,as sharing target data to be shared with a second communicationterminal, each screen data to be used for generating a drawing screenand having been generated at the first communication terminal; andsecond circuitry, residing on the second communication terminal,configured to receive selection of screen data, from among one or moreitems of screen data, as sharing target data to be shared with the firstcommunication terminal, each screen data to be used for generating adrawing screen and having been generated at the second communicationterminal. The sharing target data of the first communication terminaland the sharing target data of the second communication terminal areshared between the first communication terminal and the secondcommunication terminal.

Example embodiments include a method of sharing data, performed by thecommunication terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages and features thereof can be readily obtained and understoodfrom the following detailed description with reference to theaccompanying drawings, wherein:

FIG. 1 is a schematic diagram illustrating an example of communicationroutes in a communication system, according to an embodiment;

FIG. 2 is a diagram for describing how the electronic whiteboard is usedaccording to the embodiment;

FIG. 3 is a block diagram illustrating an example hardware configurationof an electronic whiteboard according to the embodiment;

FIG. 4 is a block diagram illustrating an example of a hardwareconfiguration of a communication management apparatus, a relay device,and an image storage device, according to the embodiment;

FIG. 5 is a diagram illustrating an example of a system configuration ofthe communication system, according to the embodiment;

FIGS. 6A and 6B (FIG. 6) are a diagram illustrating an example of afunctional configuration of the communication system according to theembodiment;

FIG. 7 is a schematic diagram illustrating an example of drawing screeninformation according to the embodiment;

FIG. 8A is a conceptual diagram illustrating an example of anauthentication management table, according to the embodiment;

FIG. 8B is a conceptual diagram illustrating an example of a terminalmanagement table, according to the embodiment;

FIG. 9A is a conceptual diagram illustrating an example of a destinationlist management table, according to the embodiment;

FIG. 9B is a conceptual diagram illustrating an example of a sessionmanagement table, according to the embodiment;

FIG. 9C is a conceptual diagram illustrating an example of a relaydevice management table, according to the embodiment;

FIG. 10 is a conceptual diagram illustrating an example of a drawingscreen information management table, according to the embodiment;

FIG. 11 is a flowchart illustrating example processing of generating adrawing screen at the electronic whiteboard, according to theembodiment;

FIGS. 12A to 12C are diagrams each illustrating an example of a drawingscreen displayed on the electronic whiteboard, according to theembodiment;

FIGS. 13A and 13B (FIG. 13) are a sequence diagram illustratingoperation for preparing to start remote communication between electronicwhiteboards, according to an embodiment;

FIG. 14 is a diagram illustrating an example of a destination listscreen displayed on the electronic whiteboard;

FIG. 15 is a sequence diagram illustrating an example operation ofstarting communication;

FIG. 16 is a flowchart illustrating example processing of selectingsharing target data, to be shared at the electronic whiteboard,according to the embodiment;

FIG. 17 is a diagram illustrating an example of a sharing target dataselection screen displayed at the electronic whiteboard, according tothe embodiment;

FIG. 18 is a sequence diagram illustrating an example operation ofsharing data between electronic whiteboards in the communication systemaccording to the embodiment;

FIG. 19 is a sequence diagram illustrating an example operation ofsharing data between electronic whiteboards in the communication systemaccording to the embodiment;

FIG. 2.0 is a sequence diagram illustrating an example operation ofsharing data between electronic whiteboards in the communication systemaccording to the embodiment;

FIG. 21 is a sequence diagram illustrating an example operation ofsharing data between electronic whiteboards in the communication systemaccording to the embodiment;

FIG. 22 is a sequence diagram illustrating an example operation ofsharing data between electronic whiteboards in the communication systemaccording to the embodiment;

FIG. 23 is a flowchart illustrating example processing of selecting atop screen at the electronic whiteboard, according to the embodiment;

FIG. 24 is a diagram illustrating an example of a top screen candidateselection screen displayed at the electronic whiteboard, according tothe embodiment; and

FIG. 25 is a diagram illustrating an example of a top screen displayedat the electronic whiteboard, according to the embodiment.

The accompanying drawings are intended to depict embodiments of thepresent invention and should not be interpreted to limit the scopethereof. The accompanying drawings are not to be considered as drawn toscale unless explicitly noted.

DETAILED DESCRIPTION

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

Embodiments of the present invention are described with reference to thedrawings. In the description of the drawings, the same elements aredenoted by the same reference numerals, and redundant descriptionsthereof are omitted.

In describing embodiments illustrated in the drawings, specificterminology is employed for the sake of clarity. However, the disclosureof this specification is not intended to be limited to the specificterminology so selected and it is to be understood that each specificelement includes all technical equivalents that have a similar function,operate in a similar manner, and achieve a similar result.

Overview:

The background communication system enables sharing of data betweencommunication terminals. For example, after a communication session isestablished to conduct videoconferencing, various types of data, such asstroke images, can be shared between the communication terminals.However, none of the above-described techniques considers which screendata is to be shared with other communication terminal, before startingsharing of such data. For example, the user may want to share data,which is only available locally, with the other party. In such case, ithas been difficult for the communication terminal to cause the othercommunication terminal to firstly display such data, at a start ofvideoconference.

Overview of Communication System:

Communication Route:

A communication system for conducting a video conference between aplurality of electronic whiteboards including an electronic whiteboard 1a and an electronic whiteboard 1 b while allowing a user to draw imageson the electronic whiteboards is described with reference to FIG. 1,FIG. 1 is a diagram illustrating an example of a communication route inthe communication system according to an embodiment. In this disclosure,the “video conference” is sometimes called a “teleconference” or “remoteconference”. The “video conference”, “teleconference”, or “remoteconference” is an example of a session in which image data and strokedata are shared between a plurality of terminals. For example, thesession in which image data and stroke data are shared may be a sessionother than a conference, such as a session in which a remote lesson, aremote medical examination, a meeting, or a casual conversation isperformed. The session in which image data and stroke data are sharedmay be used to transmit information in one direction, for example, topresent information.

The communication system includes a plurality of electronic whiteboardsincluding the electronic whiteboards 1 a and the electronic whiteboard 1b, a relay device 3, a communication management apparatus 5, and animage storage device 7. The electronic whiteboard 1 a and the electronicwhiteboard 1 b perform mutual communication of image data and audio datafor calls and content data such as image data and stroke data forsharing. The stroke data is data necessary for reproducing a strokeimage. The stroke data includes coordinate data, line width data, linecolor data, vector data, and the like. The electronic whiteboards 1 aand the electronic whiteboard 1 b exchange image data and audio data fora call with each other to reproduce an image and sound of a site wherethe communication counterpart resides, making a remote video call. Inthis disclosure, an image of a site where each of the plurality ofelectronic whiteboards such as the electronic whiteboard 1 a and theelectronic whiteboard 1 b reside may be referred to as a “site image”,hereinafter. Further, data for such site image may be referred to as“site image data”.

The electronic whiteboard 1 a and the electronic whiteboard 1 b exchangeimage data of a background image to be shared, allowing participantsusing the communication system to share the same background image. Thebackground image is an image displayed on the display of the electronicwhiteboard 1. The background image includes, for example, an image ofmaterials, in which an electronic file of meeting materials, etc. isdisplayed on the display 180. The image data of the background image istransmitted and received in a file format such as JPEG (JointPhotographic Experts Group). Further, the electronic whiteboard 1 a andthe electronic whiteboard 1 b exchange stroke data of a stroke image,allowing participants using the communication system to share the samestroke image. The stroke image is an image represented by a line or thelike drawn by a user with a handwritten stroke with such as anelectronic pen. The stroke image is displayed based on stroke datarepresenting a point on a coordinate of the display.

Although in the example of FIG. 1, the communication system includes thetwo electronic whiteboards, i.e., the electronic whiteboard 1 a and theelectronic whiteboard 1 b, in another example, the communication systemmay include three or more electronic whiteboards. The electronicwhiteboard 1 a and the electronic whiteboard 1 b are collectivelyreferred to as an “electronic whiteboard 1” or “electronic whiteboards1” hereinafter, to simplify the description, unless they need to bedistinguished from one to another. The electronic whiteboard 1 is anexample of a communication terminal having a communication function, adrawing function, a display function, and the like. Other examples ofthe communication terminal include a PC, a smartphone, a tabletterminal, a smartwatch, a car navigation system, a game machine, or atelepresence robot, each of which is installed with application programcorresponding the communication system. Further, the communicationterminal includes a medical device. In a case where the communicationterminal is a medical device, the background image is a patient image.

FIG. 1 illustrates an electronic whiteboard equipped with avideoconferencing function as an example of the electronic whiteboard 1a and the electronic whiteboard 1 b. A site image based on site imagedata can be either a moving image or a still image.

In this disclosure, an electronic whiteboard that sends a request forstarting a videoconference is referred to as a “source terminal”, and anelectronic whiteboard as a request destination to which the request isto be transmitted is referred to as a “destination terminal”. In FIG. 1,the electronic whiteboard 1 a is the source terminal and the electronicwhiteboard 1 b is the destination terminal. When the start of thevideoconference is requested from the electronic whiteboard 1 b, theelectronic whiteboard 1 b is the source terminal and the electronicwhiteboard 1 a is the destination terminal. Note that the electronicwhiteboard 1 a and the electronic whiteboard 1 b may be used not onlyfor communication between different sites or for communication betweendifferent rooms in the same site, but also for communication within thesame room or for outdoor-indoor communication or outdoor-outdoorcommunication.

The relay device 3, which is implemented by one or more computers,performs a process of relaying content data for a call between theelectronic whiteboard 1 a and the electronic whiteboard 1 b.

The communication management apparatus 5 is implemented by one or morecomputers. The communication management apparatus 5 centrally controlslogin authentication from the electronic whiteboard 1 a and theelectronic whiteboard 1 b, the communication status of each of theelectronic whiteboard 1 a and the electronic whiteboard 1 b, adestination list, the communication status of the relay device 3, andthe like. Further, the communication management apparatus 5 relaysstroke data to be shared between the electronic whiteboard 1 a and theelectronic whiteboard 1 b.

The image storage device 7, which is implemented by one or morecomputers, stores image data of a background image to be shared. Thebackground image is uploaded from the electronic whiteboard 1 a, and isdownloaded to the electronic whiteboard 1 b. Alternatively, thebackground image may be uploaded from the electronic whiteboard 1 b, andis downloaded to the electronic whiteboard 1 a. In other words, theimage storage device 7 stores the image data uploaded from theelectronic whiteboard 1 b, which is to be downloaded to the electronicwhiteboard 1 a.

In one example, each of the relay device 3, the communication managementapparatus 5, and the image storage device 7 is configured as a singlecomputer. In another example, each of the relay device 3, thecommunication management apparatus 5, and the image storage device 7 isconfigured as a plurality of computers to which one or more units(functions, means, or storages) are arbitrarily allocated. In otherwords, each of the relay device 3, the communication managementapparatus 5, and the image storage device 7 can be implemented by aplurality of servers that operate in cooperation with one another. Inthis example, the communication management apparatus 5 and the imagestorage device 7 is configured as a server system 6 that controls datato be shared the electronic whiteboard 1 a and the electronic whiteboard1 b. In the server system 6, the communication management apparatus 5and the image storage device 7 may be configured as a single computerhaving one or more units (functions or means). In alternative to thecommunication management apparatus 5, the image storage device 7 mayoperate to relay stroke data to be shared between the electronicwhiteboard 1 a and the electronic whiteboard 1 b.

In the communication system of FIG. 1, a management information sessionsei for exchanging various types of management information isestablished between the electronic whiteboard 1 a and the electronicwhiteboard 1 b through the communication management apparatus 5. Inaddition, four sessions are established between the electronicwhiteboard and the electronic whiteboard 1 b to exchange four types ofdata including site image data of high resolution, site image data ofmedium resolution, site image data of low resolution, and audio data,through the relay device 3, In FIG. 1, these four sessions arecollectively referred to as an image and audio data session sed. Notethat the video and audio data session sed does not necessarily have tobe four sessions and may have a smaller or larger number of sessionsthan the four sessions. In addition, a communication session may beestablished directly between the source terminal and the destinationterminal without intervening the relay device 3. In the communicationsystem, the communication management apparatus 5 may have a function ofthe relay device 3, such that the image and audio data session sed maybe established between the electronic whiteboard 1 a and the electronicwhiteboard 1 b through the communication management apparatus 5.

Further, in the communication system of FIG. 1, stroke data is exchangedbetween the electronic whiteboard 1 a and the electronic whiteboard 1 busing the management information session sei.

The description is now given of the resolution of an image of the siteimage data handled in the present embodiment. For example, the siteimage data of low resolution consists of 160 pixels in the horizontaldirection and 120 pixels in the vertical direction. Such site image dataof the low resolution is a base image. The site image data of mediumresolution consists of, for example, 320 pixels in the horizontaldirection and 240 pixels in the vertical direction. The site image dataof high resolution consists of, for example, 640 pixels in thehorizontal direction and 480 pixels in the vertical direction. In thecase of a narrow band path, low-quality image data that only includesthe site image data of low resolution as a base image is relayed. In thecase of a relatively wide band path, intermediate-quality image dataincluding the site image data of low resolution as a base image and thesite image data of medium resolution is relayed. In the case of a verywide band path, high-quality image data including the site image data oflow resolution as a base image, the site image data of mediumresolution, and the site image data of high resolution is relayed. Sinceaudio data is relatively small in data size compared with the site imagedata, the audio data is relayed even in the case of a narrow band path.

Use Scenario of Electronic Whiteboard:

FIG. 2 is a diagram for describing how the electronic whiteboard is usedaccording to the embodiment. As illustrated in FIG. 2, the electronicwhiteboard 1 includes a plurality of legs 151 each having a caster onthe lower side, a support 152 provided on the upper side of the legs151, a main body 153 provided on top of the support 152, and a display180 provided on the front surface of the main body 153. The main body153 includes a central processing unit (CPU) 101 and the like which isdescribed below. The user can input (draw) a stroke image such ascharacters on the display 180 using an electronic pen 190. The display180 is an example of a display (display device).

Hardware Configuration:

Next, a hardware configuration of each apparatus, device, or terminal ofthe communication system is described with reference to FIGS. 3 and 4.In the hardware configuration illustrated in FIG. 3 and FIG. 4,components or elements may be added or deleted as needed.

Hardware Configuration of Electronic Whiteboard:

FIG. 3 is a block diagram illustrating an example hardware configurationof an electronic whiteboard according to the embodiment. As illustratedin FIG. 3, the electronic whiteboard 1 includes a CPU 101, a read onlymemory (ROM) 102, a random access memory (RAM) 103, a solid state drive(SSD) 104, a network interface (I/F) 105, and an external deviceconnection IX 106.

The CPU 101 controls entire operation of the electronic whiteboard 1.The ROM 102 stores a control program for controlling the CPU 101 such asan initial program loader (IPL) to boot the CPU 101. The RAM 103 is avolatile memory used as a work area for the CPU 101. The SSD 104 is alarge capacity storage device (memory) that stores various data such asa control program for the electronic whiteboard 1. The network 11/F 105is a communication interface that connects the electronic whiteboard 1to connect to the communication network 100 to communicate with otherapparatuses. The external device connection I/F 106 is an interface forconnecting the electronic whiteboard 1 to various extraneous sources.Examples of the extraneous sources include a universal serial bus (USB)memory 130 and devices (a microphone 140, a speaker 150, and a camera160).

The electronic whiteboard 1 further includes a capture device 111, agraphics processing unit (GPU) 112, a display controller 113, a contactsensor 114, a sensor controller 115, an electronic pen controller 116, ashort-range communication circuit 119, an antenna 119 a for theshort-range communication circuit 119, a power switch 122, and selectionswitches 123.

The capture device 111 displays image data (image information) as astill image or a moving image on a display of a computer (PC) 170, whichis external to the electronic whiteboard 1. The GPU 112 is asemiconductor chip dedicated to processing of a graphical image. Thedisplay controller 113 controls display of screens to output an imageoutput from the GPU 112 to the display 180 or the like. The contactsensor 114 detects a touch on the display 180 by the electronic pen 190or a user's hand H. The sensor controller 115 controls operation of thecontact sensor 114. The contact sensor 114 senses a touch input to aspecific coordinate on the display 180 using the infrared blockingsystem. More specifically, the display 180 is provided with two lightreceiving elements disposed on both upper side ends of the display 180,and a reflector frame surrounding the sides of the display 180. Thelight receiving elements emit a plurality of infrared rays in parallelto a surface of the display 180. The light receiving elements receivelights passing in the direction that is the same as an optical path ofthe emitted infrared rays, which are reflected by the reflector frame.The contact sensor 114 outputs an identifier (ID) of the infrared raythat is blocked by an object (such as the user's hand) after beingemitted from the light receiving elements, to the sensor controller 115.Based on the ID of the infrared ray, the sensor controller 115 detects aparticular coordinate that is touched by the object. The electronic pencontroller 116 communicates with the electronic pen 190 to detect atouch by the tip or bottom of the electronic pen 190 to the display 180.The short-range communication circuit 119 is a communication circuitthat communicates in compliance with the near field communication (NFC),the Bluetooth (Registered Trademark), and the like. The power switch 122turns on or off the power of the electronic whiteboard 1. The selectionswitches 123 are a group of switches for adjusting brightness, hue,etc., of display on the display 180, for example.

The electronic whiteboard 1 further includes a bus line 110. The busline 110 is, for example, an address bus or a data bus, whichelectrically connects the elements such as the CPU 101 illustrated inFIG. 3.

The contact sensor 114 is not limited to the infrared blocking systemtype, and may be a different type of detector, such as a capacitancetouch panel that identifies the contact position by detecting a changein capacitance, a resistance film touch panel that identifies thecontact position by detecting a change in voltage of two opposedresistance films, or an electromagnetic induction touch panel thatidentifies the contact position by detecting electromagnetic inductioncaused by contact of an object to a display. In addition to or inalternative to detecting a touch by the tip or bottom of the electronicpen 190, the electronic pen controller 116 may also detect a touch byanother part of the electronic pen 190, such as a part held by a hand ofthe user.

Hardware Configuration of Communication Management Apparatus, RelayDevice, and Image Storage Device:

FIG. 4 is a block diagram illustrating an example of a hardwareconfiguration of a communication management apparatus, a relay device,and an image storage device, according to an embodiment. Thecommunication management apparatus 5 is implemented by, for example, oneor more computers. The computer includes a CPU 501, a ROM 502, a RAM503, a hard disk (HD) 504, a hard disk drive (HDD) controller 505, adisplay 506, an external device connection I/F 508, a network I/F 509, akeyboard 511, a pointing device 512, a digital versatile disc-rewritable(DVD-RW) drive 514, a medium I/F 516, and a bus line 510.

The CPU 501 controls entire operation of the communication managementapparatus 5. The ROM 502 is a non-volatile memory that stores a programfor controlling the CPU 501, such as an initial program loader (LPL).The RAM 503 is a volatile memory used as a work area for the CPU 501.The HD 504 is a large capacity storage device (memory) that storesvarious data such as a communication control program. The HDD controller505 controls reading or writing of various data to or from the HD 504under control of the CPU 501. The display 506 displays variousinformation such as a cursor, menu, window, characters, or image. Theexternal device connection I/F 508 is an interface that connects thecomputer as the communication management apparatus 5 to variousextraneous sources. The network I/F 509 is an interface for performingdata communication using the communication network 100 such as theInternet. The keyboard 511 is one example of an input device (inputmeans) provided with a plurality of keys for enabling a user to inputcharacters, numerals, or various instructions. The pointing, device 512is an example of an input device (input means) that allows a user toselect or execute a specific instruction, select a target forprocessing, or move a cursor being displayed. The DVD-RW drive 514controls reading or writing (storing) of data to the DVD-RW 513. Inanother example, a DVD-R can be used as the removal storage medium, inalternative to the DVD-RW 513, in still another example, in alternativeto or in addition to the DVD-RW drive 514, a Blu-ray (registeredtrademark) drive or a compact disc rewritable (CD-RW) drive are used tocontrol reading or writing (storing) of data with respect to a Blu-raydisc rewritable (BD-RE) or a CD-RW. The medium I/F 516 controls readingor writing (storing) of data with respect to a storage medium 515 suchas a flash memory. The bus line 510 is an address bus, a data bus or thelike, which electrically connects the elements illustrated in FIG. 4such as the CPU 501.

The relay device 3 is implemented by one or more computers. Asillustrated in FIG. 6, the relay device 3 includes a central processingunit (CPU) 301, a read only memory (ROM) 302, a random access memory(RAM) 303, a hard disk (HD) 304, a hard disk drive (HDD) controller 305,a display 306, an external device connection interface WO 308, networkI/F 309, a bus line 310, a keyboard 311, a pointing device 312, adigital versatile disc rewritable (DVD-RW) drive 314 and a medium I/F316. Since these elements are substantially similar to the CPU 501, theROM 502, the RAM 503, the HD 504, the HDD controller 505, the display506, the external device connection I/F 508, the network I/F 509, thebus line 510, the keyboard 511, the pointing device 512, the DVD-RWdrive 514, and the medium I/F 516 of the communication managementapparatus 5, redundant description thereof is omitted. The relay device3, however, stores a relay control program in the HD 304 in alternativeto the relay control program.

The image storage device 7 is implemented by one or more computers. Asillustrated in FIG. 6, the image storage device 7 includes a CPU 701, aROM 702, a RAM 703, a HD 704, a HDD controller 705, a display 706, anexternal device connection interface (I/F) 708, network I/F 709, a busline 710, a keyboard 711, a pointing device 712, a DVD-RW drive 714 anda medium I/F 716. Since these elements are substantially similar to theCPU 501, the ROM 502, the RAM 503, the HD 504, the HDD controller 505,the display 506, the external device connection I/F 508, the network I/F509, the bus line 510, the keyboard 511, the pointing device 512, theDVD-RW drive 514, and the medium I/F 516 of the communication managementapparatus 5, redundant description thereof is omitted. In addition, theimage storage device 7 stores an image storage control program in theHI) 704 in alternative to the communication control program.

Further, any one of the above-described control programs may be recordedin a file in a format installable or executable on a computer-readablestorage medium for distribution. Examples of the storage medium include,but not limited to, compact disc-recordable (CD-R), DVD, Blu-ray disc,and secure digital (SD) card. In addition, such storage medium may beprovided in the form of a program product to users within a certaincountry or outside that country. For example, the communication terminalsuch as the electronic whiteboard executes the control program toimplement a screen sharing method according to the present disclosure.

Overview of Configuration of Communication System:

A description is now given of an overall configuration of thecommunication system with reference to FIG. 5, according to anembodiment. FIG. 5 is a diagram illustrating an example of a systemconfiguration of the communication system, according to the embodiment.

In FIG. 5, the electronic whiteboard 1 a is provided at a site A, andthe electronic whiteboard 1 b is provided at a site B. For example, thesite A is a Tokyo office in Japan, and the site B is a Beijing office inChina. Further, a user A1 uses the electronic whiteboard 1 a at the siteA, and users B1 and B2 use the electronic whiteboard 1 b at the site B.

The electronic whiteboard 1 a, the electronic whiteboard 1 b, the relaydevice 3, the communication management apparatus 5, and the imagestorage device 7 mutually communicate data through the communicationnetwork 100 such as the Internet or LAN. The communication network 100may not only include a wired network, but also a wireless network suchas a network in compliance with \Vi-Fi (registered trademark) or thelike.

Functional Configuration of Communication System:

A description is now given of a functional configuration of thecommunication system according to embodiments, with reference to FIG. 6Ato FIG. 10. FIG. 6 is a diagram illustrating an example of a functionalconfiguration of the communication system according to the embodiment.FIG. 6 illustrates a terminal, an apparatus, and a server that relate toprocesses or operations to be described below among the terminals,apparatuses, and servers illustrated in FIG. 5.

Functional Configuration of Electronic Whiteboard:

First, referring to FIG. 6, a description is given of the functionalconfiguration of the electronic whiteboard 1 according to theembodiment. Since the functions of the electronic whiteboards 1 a and 1b are the same, the functions of the electronic whiteboard 1 will bedescribed here. The electronic whiteboard 1 includes a sharing unit 11,an acceptance unit 12, a video/audio processing unit 13, a displaycontrol unit 14, a determination unit 15, an image processing unit 16, ashort-range communication unit 18, and a storing/reading processing unit19. These units are functions implemented by or caused to function byoperating any of the hardware elements illustrated in FIG. 3 incooperation with the instructions of the CPU 101 according to thecontrol program expanded from the SSD 104 to the RAM 103. The electronicwhiteboard 1 further includes a storage unit 1000, which is implementedby the RAM 103, the SSD 104, or the USB memory 130 illustrated in FIG.3.

The sharing unit 11, which is implemented by instructions of the CPU 101and by the network IX 105 illustrated in FIG. 3, controls sharing ofvarious types of data (or information) with other terminal, device,apparatus, or system through the communication network 100. For example,the sharing unit 11 shares screen data, such as screen data to be usedfor such as drawing, to be displayed on the display 180, with otherelectronic whiteboard 1. The screen data used for such as drawing(referred to as the drawing screen data) is screen data that allows auser to draw strokes, such that the screen data may include a strokeimage. The sharing unit 11 also functions as a communication startingunit, for example, and performs a process of starting communication withother electronic whiteboard 1. For example, the sharing unit 11, whichfunctions as a data exchange unit, transmits or receives screen data tobe shared with other electronic whiteboard 1 via the communicationmanagement apparatus 5.

The acceptance unit 12, which is implemented by instructions of the CPU101, by the contact sensor 114, and by the electronic pen controller 116illustrated in FIG. 3, receives various inputs from the user, which isinput with such as the electronic pen 190. As the user moves such as theelectronic pen 190 in contact with the display 180, the acceptance unit12 accepts an input of a stroke movement (trajectory). For example, theacceptance unit 12 accepts a selection on, for example, various types ofselection screens, displayed on the display 180.

The video/audio processing unit 13 is implemented by instructions fromthe CPU 101 illustrated in FIG. 3, and performs processing to conductvideo conference. For example, the video/audio processing unit 13performs digital processing such as encoding of site image data andaudio data in accordance with the output signal of the microphone 140and the output signal of the camera 160. Further, the video/audioprocessing unit 13 generates an image signal and an audio signal basedon the site image data and the audio data received at the sharing unit11. The video/audio processing unit 13 a performs processing forcombining site image data having different resolutions.

The display control unit 14 is implemented by instructions of the CPU101 and by the display controller 113 illustrated in FIG. 3, andcontrols output of an image signal to the display 180, for example. Forexample, the display control unit 14 controls the display 180 to displaya screen for drawing, based on drawing screen data generated at theimage processing unit 16. The determination unit IS, which isimplemented by instructions of the CPU 101 illustrated in FIG. 3, has afunction of making various determinations.

The image processing unit 16 is implemented by instructions from the CPU101 and the capture device 111 illustrated in FIG. 3, and performsprocessing related to functions of the electronic whiteboard. Forexample, the image processing unit 16 generates stroke data and a strokeimage based on a stroke of the electronic pen 190 or the like, acceptedby the acceptance unit 12 a. Alternatively, the image processing unit 16generates a stroke image based on stroke data received by the sharingunit 11.

The short-range communication unit 18, which is implemented byinstructions of the CPU 101 and the short-range communication circuit119 with the antenna 119 a, illustrated in FIG. 3, communicates with aterminal device carried by the user, such as an IC card or a smartphone,to obtain or provide data from or to the IC card or the smartphone byshort-range communication.

The storing/reading processing unit 19, which is implemented byinstructions of the CPU 101 illustrated in FIG. 3, has a function ofstoring various data in the storage unit 1000, and reads various datafrom the storage unit 1000. Further, every time site image data andaudio data are received in performing communication with other terminal,the storing/reading processing unit 19 overwrites the site image dataand audio data stored in the storage unit 1000. The display 180 displaysan image based on site image data before being overwritten. The speaker150 outputs sound based on audio data before being overwritten. Thestorage unit 1000 further stores stroke data corresponding to a strokeimage drawn on the display 180 and background image data correspondingto a background image displayed on the display 180.

Drawing Screen Information:

FIG. 7 is a schematic diagram illustrating an example of drawing screeninformation according to the embodiment. FIG. 7 illustrates an exampleimage of a drawing screen displayed on the electronic whiteboard 1,based on information stored in the drawing screen management DB 1001.

As illustrated in the example of FIG. 7, the drawing screen has ahierarchical structure, classified by “conference”, “page (pages 1 to4)”, and “stroke (strokes 1 to 5)”. The “stroke” corresponds to strokedata in this embodiment, and is managed for each “page”. The “page”represents a one-page screen (display screen) displayed on the display180. The “conference” represents information on a conference beingconducted using the electronic whiteboard 1. For example, the stroke 1includes, for example, a stroke ID (id=sr001) for identifying stroke 1,information (parent=pag01) for identifying page 1 where stroke 1 exists,gid (global id) “G001” of drawing data 1, and drawing data 1. Forexample, when operation such as movement is performed on the strokeimage represented by the stroke 1, the stroke ID (id=sr001) is inheritedas it is, but the gid “g001.” for identifying the drawing data 1 and thedrawing data 1 are each updated. The drawing data 1 is drawing data forreproducing the stroke 1. The drawing data 1 includes, for example,coordinate data, line width data, line color data, vector data, and thelike.

The electronic whiteboard 1 can switch pages, and the “page” correspondsto each page of the electronic whiteboard 1. For example, the page 1includes a page ID (id=pag01) for identifying page 1, information(parent=se0) for identifying a “conference” being conducted at theelectronic whiteboard 1, gid “g01” for identifying a page (page data),and image data 1. The image data 1 is image data of a background imagecontained in the page 1. That is, the image data 1 represents thebackground image displayed on the page 1. In this example, the page 2does not include image data. This means that the page 2 has nobackground image (or a blank background).

The “conference” corresponds to the conference being conducted at theelectronic whiteboard 1, and is managed using the conference ID foridentifying the conference and the gid “g1” of the conference(conference information). Further, when the electronic whiteboard 1communicates remotely with other electronic whiteboard, the conferenceID corresponds to the session ID (id=se01) for identifying the session.For example, the image processing unit 16 of the electronic whiteboard 1can generate the stroke image drawn on the page 1 by using the drawingdata 1 to 5 included in the strokes 1 to 5. The gid (global id) in eachlayer is assigned by the communication management apparatus 5 when thescreen data is shared with other electronic whiteboard. Further, thehierarchical structure of the drawing screen information in FIG. 7 isshared between a plurality of electronic whiteboards 1 when screen datais shared.

Functional Configuration of Relay Device:

Referring to FIG. 6, a functional configuration of the relay device 3 isdescribed according to the embodiment. The relay device 3 includes adata exchange unit 31, which also functions as a transfer unit, adetermination unit 35, and a storing/reading processing unit 39. Theseunits are functions implemented by or caused to function by operatingany of the hardware elements illustrated in FIG. 4 in cooperation withthe instructions of the CPU 301 according to the relay control programexpanded from the HD 304 to the RAM 303. Further, the relay device 3includes a storage unit 3000 implemented by the RAM 303, the HD 304, orthe recording medium 315, illustrated in FIG. 4.

The data exchange unit 31, which is implemented by instructions of theCPU 301 and by the network I/F 309 illustrated in FIG. 4, transmits orreceives various types of data (or information) to or from otherterminal, device, apparatus, or system through the communication network100. The data exchange unit 31 also functions as a transfer unit, andtransfers site image data and audio data transmitted from one terminalto another terminal. The determination unit 35, which is implemented byinstructions of the CPU 301 illustrated in FIG. 4, has a function ofmaking various determinations such as determination of whether delay indata transmission has occurred.

The storing/reading processing unit 39, which is implemented byinstructions of the CPU 301 illustrated in FIG. 4, has a function ofstoring various data in the storage unit 3000, and reads various datafrom the storage unit 3000.

Functional Configuration of Communication Management Apparatus:

Referring to FIG. 6, a functional configuration of the communicationmanagement apparatus 5 is described according to the embodiment. Thecommunication management apparatus 5 includes a data exchange unit 51,an authentication unit 52, a determination unit 53, a terminalmanagement unit 54, a session management unit 55, a relay devicemanagement unit 56, a drawing screen management unit 57, and astoring/reading processing unit 59. These units are functionsimplemented by or caused to function by operating any of the hardwareelements illustrated in FIG. 4 in cooperation with the instructions ofthe CPU 501 according to the communication control program expanded fromthe HD 504 to the RAM 503. Further, the communication managementapparatus 5 includes a storage unit 5000 implemented by the RAM 503, theHD 504, or the storage medium 515, illustrated in FIG. 4.

The data exchange unit 51, which is implemented by instructions of theCPU 501 and by the network I/F 509 illustrated in FIG. 4, transmits orreceives various types of data (or information) to or from otherterminal, device, apparatus, or system through the communication network100. For example, the data exchange unit 51 controls transmission orreception of stroke data between the electronic whiteboard 1 and otherelectronic whiteboard.

The authentication unit 52, which is implemented by instructions of theCPU 501 illustrated in FIG. 4, authenticates a login request sourceterminal, which sends a request for login to the communicationmanagement apparatus 5. Specifically, in response to receiving loginrequest information at the data exchange unit 51, the authenticationunit 52 authenticates the login request source terminal usinginformation registered in the authentication management DB 5001. Thedetermination unit 53, which is implemented by instructions of the CPU501 illustrated in FIG. 4, has a function of making variousdeterminations.

The terminal management unit 54, which is implemented by instructions ofthe CPU 501 illustrated in FIG. 4, manages various information on theelectronic whiteboard 1 stored in the terminal management DB 5002according to a state of the electronic whiteboard 1. For example, theterminal management unit 54 updates information stored in the terminalmanagement DB 5002, such as an operating status, a date and time ofreception, and an IP address of a terminal. Further, the terminalmanagement unit 54 manages the destination list management DB 5003, andprovides destination list information including a terminal ID of one ormore destination terminals managed by the destination list management DB5003 in response to a request from the electronic whiteboard 1.

The session management unit 55, which is implemented by instructions ofthe CPU 501 illustrated in FIG. 4, manages a session held in thecommunication system. For example, the session management unit 55generates a session ID for identifying a session, according to startrequest information requesting the start of communication by theelectronic whiteboard 1. Further, the session management unit 55 storesand manages, for the session ID of each session, various informationrelated to the session in the session management DB 5004.

The relay device management unit 56, which is implemented byinstructions of the CPU 501 illustrated in FIG. 4, has a function ofselecting the relay device 3 to be used for relaying data in aparticular session from among the plurality of relay devices 3. Forexample, the relay device management unit 56, which manages the relaydevice management DB 5005, selects one relay device 3 using variousinformation regarding each relay device 3 stored in the relay devicemanagement DB 5005. In one example, the relay device management unit 56selects the relay device 3 residing near the source terminal, based onthe IP address of each relay device 3 stored in the relay devicemanagement DB 5005 and the IP address of the source terminal, forexample. In another example, the relay device management unit 56 selectsthe relay device 3 based on, for example, the maximum data transmissionrate of each relay device 3 stored in the relay device management DB5005. The relay device 3 used for relaying data in the session may beselected in any other method. Further, the number of relay devices 3included in the communication system may be one.

The drawing screen management unit 57, which is implemented byinstructions of the CPU 501 illustrated in FIG. 4, manages various dataor information related to the drawing screen transmitted and receivedbetween the electronic whiteboards 1 (communication terminals). Thedrawing screen management unit 57 stores, for example, the stroke datatransmitted from the electronic whiteboard 1 participating in thesession sei, in the drawing screen information management DB 5006 inassociation with the session ID for management.

The storing/reading processing unit 59, which is implemented byinstructions of the CPU 501 illustrated in FIG. 4, has a function ofstoring various data in the storage unit 5000, and reads various datafrom the storage unit 5000.

Authentication Management Table:

FIG. 8A is a conceptual diagram illustrating an example of anauthentication management table, according to the embodiment. Thestorage unit 5000 stores an authentication management database (DB)5001, which is implemented by the authentication management table asillustrated in FIG. 8A. The authentication management table stores, foreach one of the electronic whiteboards 1 managed by the communicationmanagement apparatus 5, a terminal ID of the electronic whiteboard and apassword in association with each other. For example, the authenticationmanagement table illustrated in FIG. 8A indicates that the terminal IDof the electronic whiteboard 1 a (communication terminal) is “01aa.” andthe password of the electronic whiteboard 1 a is “aaaa”. The password isan example of authentication information. The authentication informationalso includes an access token.

Terminal Management Table:

FIG. 8B is a conceptual diagram illustrating an example of a terminalmanagement table, according to the embodiment. The storage unit 5000stores a terminal management DB 5002, which is implemented by theterminal management table as illustrated in FIG. 8B. The terminalmanagement table stores, for each one of the terminal IDs identifyingthe electronic whiteboards 1 (communication terminals), a terminal nameto be used when each electronic whiteboard 1 is a destination terminal,an operating status of each electronic whiteboard 1, reception date andtime when login request described below is received by the communicationmanagement apparatus 5, and the internet protocol (IP) address of eachelectronic whiteboard 1 (communication terminal) in association witheach other. For example, the terminal management table illustrated inFIG. 8B indicates that the electronic whiteboard 1 a whose terminal IDis “01aa” has the terminal name “JAPAN TOKYO OFFICE TERMINAL AA” and theoperating status of the electronic whiteboard 1 a is “Online (Ready)”.Further, the terminal management table indicates that the date and timewhen the login request is received by the communication managementapparatus 5 is “13:40 on Feb. 10, 2019” and the IP address of theelectronic whiteboard 1 a is “1.2.1.3”. The terminal ID, the terminalname, and the IP address of the communication terminal are stored wheneach electronic whiteboard 1 is pre-registered to receive serviceprovided by the communication management apparatus 5.

Destination List Management Table:

FIG. 9A is a conceptual diagram illustrating an example of a destinationlist management table, according to an embodiment. The storage unit 5000stores a destination list management DB 5003, which is implemented bythe destination list management table as illustrated in FIG. 9A. Thedestination list management table stores the terminal ID of the sourceterminal (electronic whiteboard 1) that sends a request for a start ofcommunication in association with the terminal IDs of all destinationterminals (electronic whiteboards 1) registered as destination terminalcandidates for the source terminal. For example, the destination listmanagement table illustrated in FIG. 9A indicates that the destinationterminal candidates to which the source terminal (electronic whiteboard1 a) whose terminal ID is “01aa” can send the request for the start ofcommunication are the electronic whiteboard 1 b whose terminal ID is “01ha”, etc. The destination terminal candidates are updated by addition ordeletion in response to an addition or deletion request transmitted fromany source terminal to the communication management apparatus 5.

The destination list is an example of destination information. Inanother example, the destination information can be managed in variousways other than the list format as illustrated in FIG. 9A, as long asinformation on destination such as a terminal ID can be obtained.

Session Management Table:

FIG. 9B is a conceptual diagram illustrating an example of a sessionmanagement table, according to the embodiment. The storage unit 5000stores a session management DB 5004, which is implemented by the sessionmanagement table as illustrated in FIG. 9B. The session management tablestores, for each session ID for identifying a session to perform mutualcommunication between each electronic whiteboard 1 (communicationterminal) and the relay device 3, a relay device ID of the relay device3 to be used, a source terminal ID of the electronic whiteboard 1(source terminal), a destination terminal ID of electronic whiteboard 1(destination terminal), a delay time (ms) in receiving site image dataat the destination terminal, and reception date and time when delayinformation indicating this delay time is transmitted from thedestination terminal and received by the communication managementapparatus 5, in association. For example, the session management tableillustrated in FIG. 9B indicates that, in a communication sessionidentified with the session ID “se01”, the relay device with the relaydevice ID “111a” relayed site image data and audio data between theelectronic whiteboard with the terminal ID “01aa” and the electronicwhiteboard with the terminal ID “01db”, the delay time of the site imagedata received by the electronic whiteboard (destination terminal) at“13:41 on Feb. 10, 2019” was 200 ms.

Relay Device Management Table:

FIG. 9C is a conceptual diagram illustrating an example of a relaydevice management table, according to the embodiment. The storage unit5000 stores a relay device management DB 5005, which is implemented bythe relay device management table as illustrated in FIG. 9C. The relaydevice management table stores, for each one of the relay devices 3, therelay device ID, the operating status of the relay device 3, the dateand time when the communication management apparatus 5 received statusinformation indicating the operating status, an IP address of the relaydevice 3, and maximum data transmission rate (Mbps) of the relay device3, in association. For example, the relay device management tableillustrated in FIG. 9C indicates that the relay device 3 whose relaydevice ID is “111a” has the operation status

“Online”, the date and time when the communication management apparatus5 received the operating status is “13:30 on Feb. 10, 2019”, the IPaddress of the relay device 3 is “1.2.1.2”, and the maximum datatransmission rate of the relay device 3 is 100 Mbps.

Drawing Screen Information Management Table:

FIG. 10 is a conceptual diagram illustrating an example of a drawingscreen information management table, according to the embodiment. Thestorage unit 5000 stores a drawing screen information management DB5006, which is implemented by the drawing screen information managementtable as illustrated in FIG. 10. The drawing screen informationmanagement table stores, for each session ID identifying a session toperform mutual communication between each electronic whiteboard 1(communication terminal) and the relay device 3, various data related toa drawing screen to be shared between the electronic whiteboards 1.Various data in the drawing screen information management tablecorrespond to a state of the drawing screen stored in the drawing screenmanagement DB 1001 for each electronic whiteboard 1 (FIG. 7).

For example, the drawing screen information management table includes anID for identifying each data, a sequence number indicating an orderdetermined by time when each data was generated, information (body)indicating the content of each data, and information (parent) foridentifying a parent (root) of each data. For example, in the case ofconference information indicating a video conference being executed by aplurality of electronic whiteboards 1, the drawing screen informationmanagement table includes a conference ID (session ID) for identifyingthe conference being executed, information (children) indicating one ormore pages having been generated at the conference, and information(current page) indicating a page of the drawing screen currentlydisplayed on the electronic whiteboard 1. In another example, in thecase of page data, the drawing screen information management tableincludes a page ID for identifying a page (page data), and a URL(Uniform Resource Locator) indicating the storage location of backgroundimage data of that page.

In another example, in the case of stroke data, the drawing screeninformation management table includes a stroke ID for identifying thestroke data generated by the “stroke drawing” event, information (body)indicating the content of the stroke data, and information (parent)identifying a parent page (page data). In this case, the information(body) indicating the content of the stroke data includes a color of thedrawn stroke, a width indicating the line thickness of the drawn stroke,and a vertex (x, y) of the drawn stroke.

In the embodiment, the “stroke drawing” is processing of inputtingdrawing data by a user. For example, the stroke drawing is an eventdetected from when a user presses the electronic pen 190 against thedisplay 180 and moves the electronic pen 190 with the electronic pen incontact with the surface of the display 180 until when the user releasesthe electronic pen 190 from the display 180. The color of the stroke isrepresented in a data format of RGBA (Red Green Blue Alpha), and eachelement is represented by a numerical value of 0 to 255. Further, thewidth of the line of the drawn stroke is represented by the number ofpixels. The vertices of the drawn stroke are represented by X-Ycoordinates. A Bezier curve obtained from the vertices forms a linesegment indicating the stroke. Using this drawing screen informationmanagement table, the communication management apparatus 5 managesvarious data relating to a drawing screen, including stroke datagenerated during a video conference, conducted through a particularcommunication session.

Functional Configuration of Image Storage Device:

Referring to FIG. 6, a functional configuration of the image storagedevice 7 is described according to the embodiment. The image storagedevice 7 includes a data exchange unit 71, a generation unit 73, and astoring/reading processing unit 79. These units are functions that areimplemented by or that are caused to function by operating any of theelements illustrated in FIG. 4 in cooperation with instructions of theCPU 701 according to the image storage device control program expandedfrom the HD 704 to the RAM 703. Further, the image storage device 7includes a storage unit 7000 implemented by the RAM 703, the HD 704, orthe recording medium 715, illustrated in FIG. 4.

The data exchange unit 71, which is implemented by instructions of theCPU 701 and by the network I/F 709 illustrated in FIG. 4, transmits orreceives various types of data (or information) to or from otherterminal, device, apparatus, or system through the communication network100. The generation unit 73, which is implemented by the instructions ofthe CPU 701 illustrated in FIG. 4, generates a URL indicating thestorage location of the background image data. The storing/readingprocessing unit 79, which is implemented by instructions of the CPU 701illustrated in FIG. 4, has a function of storing various data in thestorage unit 7000, and reads various data from the storage unit 7000.

Operation:

Referring to FIGS. 11 to 25, operation performed by the communicationsystem is described according to the embodiment.

Processing to Generate Drawing Screen:

First, referring to FIGS. 11 and 12A to 12C, processing of generating adrawing screen by the electronic whiteboard 1 before starting remotecommunication with other electronic whiteboard 1 is described accordingto the embodiment. FIG. 11 is a flowchart illustrating exampleprocessing of generating a drawing screen at the electronic whiteboard.

In the following, it is assumed that the user A at site A has started aconference using the electronic whiteboard 1 a, before starting remotecommunication with other electronic whiteboard 1 b. Before startingremote communication, it is assumed that each of the electronicwhiteboard 1 a and the electronic whiteboard 1 b generates a drawingscreen as described below.

First, the image processing unit 16 of the electronic whiteboard 1generates conference information on the conference being conducted(S111). The conference information includes a conference ID foridentifying the conference being conducted at the electronic whiteboard1. Next, the image processing unit 16 generates page information on apage displayed on the display 180 (S112). The page information includesa page ID for identifying a particular page, and information (parent)for identifying a conference being conducted at the electronicwhiteboard 1.

The display control unit 14 controls the display 180 to display abackground image of the drawing screen (S113). The image data of thebackground image being displayed is associated with the page informationgenerated at S112.

Next, as the user moves the electronic pen 190 or the user's hand H incontact with the display 180 of the electronic whiteboard 1, theacceptance unit 12 accepts an input of a stroke movement (trajectory)(YES at S114), and the operation proceeds to S115. The image processingunit 16 generates stroke data (for example, coordinate data (x, y)) fordisplaying a stroke image on the two-dimensional display 180 based onthe stroke input and accepted at the acceptance unit 12 (S115). Thestroke data includes a stroke ID for identifying the stroke andinformation (parent) for identifying the page (page data) where thestroke (stroke image) is present. The display control unit 14 controlsthe display 180 of the electronic whiteboard 1 to display the strokeimage based on the stroke data (S116). The drawing data of the strokeimage being displayed is associated with the stroke data generated atS115, In this case, the display 180 displays a drawing screen includingthe background image and the stroke image.

On the other hand, when the acceptance unit 12 does not accept input ofthe stroke at S114 (NO at S114), the operation proceeds to S117. In thiscase, the display 180 displays a drawing screen including only thebackground image.

Next, the determination unit 15 determines whether the page displayed onthe display 180 has changed (S117). For example, the determination unit53 determines that the page has changed when the acceptance unit 12accepts a request to generate a new page or when the display 180displays a different background image. When the determination unit 15determines that the page has not changed (NO at S117), the operationproceeds to S118. When the determination unit 15 determines that thepage has changed (YES at S117), the operation from S112 is repeated tonewly generate page information on the updated page.

Next, the determination unit 15 determines whether or not the conferencehas ended (S118). For example, the determination unit 15 determines thatthe conference has ended when the acceptance unit 12 receives a requestto end the conference or when the electronic whiteboard 1 is poweredoff. When the determination unit 15 determines that the conference hasnot ended (NO at S118), the operation from S114 is repeated, and theconference using the displayed page is continued. On the other hand,when the determination unit 15 determines that the conference has ended(YES at S118), the operation ends.

As described above, during a conference being conducted at a particularsite, the electronic whiteboard 1 generates the drawing screeninformation illustrated in FIG. 7 and displays the corresponding drawingscreen on the display 180, to allow the user to draw a stroke whiledisplaying a background image.

Referring now to FIGS. 12A to 12C, an example of a drawing screen,generated through processing of FIG. 11 and displayed at the electronicwhiteboard 1, is described. The drawing screen 200A illustrated in FIG.12A includes a background image v1 and a stroke image st1. The drawingscreen 200B illustrated in FIG. 12B includes a stroke image st2. Thedrawing screen 200C illustrated in FIG. 12C includes a background imagev3 and a stroke image st3. Further, the electronic whiteboard 1 managesscreen data (background image data and stroke data) to be used forgenerating a drawing screen displayed on the display 180 as the drawingscreen information illustrated in FIG. 7. For example, the drawingscreen 200A illustrated in FIG. 12A is a drawing screen made up of thescreen data of “page 1”, the drawing screen 200B illustrated in FIG. 129is a drawing screen made up of the screen data of “page 2”, and thedrawing screen 200C illustrated in FIG. 12C is a drawing screen made upof the screen data of “page 3”.

As described above, the electronic whiteboard 1 is able to display aplurality of drawing screens as illustrated in FIGS. 12A to 12C. Thedrawing screens 200A to 200C illustrated in FIGS. 12A to 12C areexamples of display screens displayed on the display 180.

Operation of Preparing for Remote Communication:

First, a description is given of operation of preparing for remotecommunication, performed by the electronic whiteboard 1 a as a loginrequest sender terminal, with reference to FIGS. 13A and 13B and FIG.14. FIGS. 13A and 13B are a sequence diagram illustrating operation forpreparing to start remote communication between the electronicwhiteboards. FIG. 14 is a diagram illustrating an example of adestination list screen displayed on the electronic whiteboard. Theelectronic whiteboard 1 b performs login operation in the same orsubstantially the same manner as the electronic whiteboard 1 a, and thusthe redundant description thereof is omitted below.

As the power switch 122 of the electronic whiteboard 1 a is turned on,the acceptance unit 12 a accepts a request to turn on the power of theelectronic whiteboard 1 a (S11).

The sharing unit 11 a transmits login request information indicating arequest for login authentication to the communication managementapparatus 5 through the communication network 100 (S12). The loginrequest information includes the terminal ID of the electronicwhiteboard 1 a and the password. The terminal ID and the password aredata that have been read via the storing/reading processing unit 19 afrom the storage unit 1000 a and sent to the sharing unit 11 a. Inanother example, a terminal ID and/or a password input by the user usingan input device (input means) such as a key board may be transmitted. Instill another example, a terminal ID and/or a password read from astorage medium such as a subscriber identity module (SIM) card or an SDcard connected to the electronic whiteboard 1 a may be transmitted.Thereby, the data exchange unit 51 of the communication managementapparatus 5 receives the login request information transmitted from theelectronic whiteboard 1 a.

Next, the authentication unit 52 of the communication managementapparatus 5 searches the authentication management table (FIG. 8A) usingthe terminal ID and the password included in the login requestinformation received via the data exchange unit 51 as search keys. Whenthe combination of the terminal ID and the password included in thelogin request information is registered in the authentication managementtable, the authentication unit 52 permits the login of the electronicwhiteboard 1 a (S13). Here, when the combination of the terminal ID andthe password included in the login request information is registered inthe authentication management table, operation subsequent to S14 isperformed.

When the login of the electronic whiteboard 1 a is allowed, the terminalmanagement unit 54 updates information associated with the terminal ID“01aa” of the electronic whiteboard 1 a in the terminal management table(FIG. 8B). For example, the terminal management unit 54 changes theoperating status of the terminal ID “01aa” to “Online (Ready)” andupdates the reception date and time to indicate the date and time whenthe login request information is received (S14). Here, the IP address ofthe communication terminal (electronic whiteboard) may not be the IPaddress that is previously registered, but may be the IP address that istransmitted from the electronic whiteboard 1 a at S12. As illustrated inFIG. 8B, in the terminal management table, the terminal ID “01aa”, theoperating status “Online (Ready)”, the reception date and time“2019.2.10.13:40”, and the IP address “1.2.1.3” are stored inassociation with each other.

The storing/reading processing unit 55 adds a new record including theterminal ID “01aa” of the electronic whiteboard 1 a received at S12 inthe session management table as illustrated in FIG. 9B (S15). The dataexchange unit 51 transmits the authentication result informationindicating the authentication result obtained at S13 to the electronicwhiteboard 1 a that has sent the login request information through thecommunication network 100 (S16).

When the sharing unit 11 a of the login request sender terminal(electronic whiteboard 1 a) receives the authentication resultindicating that login of the communication terminal (electronicwhiteboard 1 a) is permitted, the sharing unit 11 a transmitsdestination list request information indicating a request for adestination list to the communication management apparatus 5 through thecommunication network 100 (S17). Accordingly, the data exchange unit 51of the communication management apparatus 5 receives the destinationlist request information.

Next, the terminal management unit 54 searches the destination listmanagement table (FIG. 9A) using the terminal ID “01aa” of theelectronic whiteboard 1 a (login request sender terminal) as a searchkey, and reads out the terminal ID of one or more destination terminalcandidates that can communicate with the login request sender terminal(electronic whiteboard 1 a). The terminal management unit 54 furtherreads out the destination name associated with the terminal ID of theone or more destination terminal candidates from the terminal managementtable (FIG. 8B) (S18). As a result, the terminal ID and terminal name ofeach of the destination terminal candidates corresponding to theterminal ID “01aa” of the login request sender terminal (electronicwhiteboard 1 a) are extracted.

Next, the data exchange unit 51 reads, for example, destination listframe data and icon data indicating the operating status from thestorage unit 5000 through the storing/reading processing unit 59 (S19).The data exchange unit 51 transmits destination list informationincluding the destination list frame and the icons being read, and theterminal IDs and the terminal names extracted at S18, to the loginrequest sender terminal (electronic whiteboard 1 a) (520). Accordingly,the sharing unit 11 a of the login request sender terminal (electronicwhiteboard 1 a) receives the destination list information. Thestoring/reading processing unit 19 a stores the destination listinformation that is received in the storage unit 1000 a (S21).

As described above, in the present embodiment, the communicationmanagement apparatus 5 centrally manages the destination listinformation of all terminals, instead of that each terminal manages thedestination list information. For example, when a new electronicwhiteboard 1 is added to the communication system, when a terminalalready included in the communication system is replaced with a newmodel, or when appearance of the destination list frame is to bechanged, since the communication management apparatus 5 according to thepresent embodiment centrally manages all destination candidates, timeand efforts otherwise required for each terminal to change thedestination list information can be saved.

The storing/reading processing unit 54 searches the terminal managementtable (FIG. 8B) using the terminal IDs of the destination terminalcandidates read at S18 as search keys, to read the operating statusassociated with the terminal ID of each of the destination terminalcandidates. By this searching, the terminal management unit 54 acquiresthe operating status of each electronic whiteboard 1 associated with theterminal II) of each destination terminal candidate (S22).

The data exchange unit 51 transmits terminal status informationincluding the terminal IDs that are used as the search keys at S22 andthe operation statuses of the corresponding destination terminalsthrough the communication network 100 to the login request senderterminal (electronic whiteboard 1 a) (S23).

Next, the storing/reading processing unit 19 a of the login requestsender terminal (electronic whiteboard 1 a) successively stores theoperation status information of the terminals received from thecommunication management apparatus 5 in the storage unit 1000 a (S24).As a result, the login request sender terminal (electronic whiteboard 1a) acquires the operation status of the destination terminal candidate(electronic whiteboard 1 b) that can communicate with the login requestsender terminal (electronic whiteboard 1 a).

Next, the display control unit 14 a of the login request sender terminal(electronic whiteboard. 1 a) generates a destination list reflecting theoperation statuses of the destination terminal candidates based on thedestination list information and the operation status information storedin the storage unit 1000 a. Further, the display control unit 14 adisplays a destination list screen 800 as illustrated in FIG. 14 on thedisplay 180 of the electronic whiteboard 1 a using the destination listthat is generated (S25). On the destination list screen 800, the iconindicating the operation status, the terminal ID, and the terminal nameare displayed for each destination terminal candidate. In the example ofFIG. 14, the icons representing the operation statuses of thecommunication terminals displayed from the top of the screen indicatethe operation status “Offline”, “Online (Ready)”, and “Online (Ready)”,

The storing reading processing unit 54 of the communication managementapparatus 5 searches the destination list management table (FIG. 9A)based on the terminal ID “01aa” of the login request sender terminal(electronic whiteboard 1 a), to obtain the terminal IDs of othercommunication terminals that have registered the terminal ID “01aa” ofthe login request sender terminal (electronic whiteboard 1 a) as thedestination terminal candidate (S26). In the destination list managementtable illustrated in FIG. 9,4, the terminal IDs of other terminals to beread at S26 are “01 ab” “01ba”, and “01 ca”.

The storing/reading processing unit 54 searches the terminal managementtable (FIG. 8B) based on the terminal ID “01aa” of the login requestsender terminal (electronic whiteboard 1 a), to acquire the operationstatus of the login request source terminal (electronic whiteboard 1 a)(S27).

The data exchange unit 51 transmits the terminal status informationincluding the terminal ID “01aa” of the login request sender terminal(electronic whiteboard 1 a) and the terminal status information of theterminal having the operation status “Online” acquired at S27, to thecommunication terminal(s) whose operation status is “Online” in theterminal management table (FIG. 8B), from among the communicationterminals identified by the terminal IDs extracted at S26 (S28). Whenthe data exchange unit 51 transmits the terminal status information tothe electronic whiteboard 1 b, the IP address of the electronicwhiteboard stored in the terminal management table (FIG. 8B) is referredto based on each terminal ID. Thus, the terminal ID “01aa” and theoperation status “Online” of the login request sender terminal(electronic whiteboard 1 a) are transmitted to each of the otherdestination terminals that can communicate with the login request senderterminal (electronic whiteboard 1 a) as a destination terminalcandidate. Accordingly, the operation status of the other destinationterminal candidate is displayed on the destination terminal candidate(such as the electronic whiteboard 1 b) (S29).

While the above-described processing describes the case in which theelectronic whiteboard 1 a is powered on, preparation for starting remotecommunication may be performed at any time, for example, right after theprocessing of FIG. 11. In such case, login processing and authenticationprocessing may be omitted.

Operation of Starting Remote Communication:

A description is now given of operation in which the electronicwhiteboard 1 a starts remote communication with the electronicwhiteboard 1 b, with reference to FIG. 15. FIG. 15 is a sequence diagramillustrating an example operation of starting communication.

As the user A1 of a request source terminal (electronic whiteboard 1 a)selects the electronic whiteboard 1 b by selecting a destinationterminal candidate (terminal ID “01ba”) illustrated in FIG. 14, theacceptance unit 12 a accepts a request to start communication with theselected destination terminal (electronic whiteboard 1 b) (S31). Thesharing unit 11 a of the request source terminal (electronic whiteboard1 a) transmits start request information indicating a request forstarting communication to the communication management apparatus 5(S32). The start request information includes the terminal ID “01aa” ofthe request source terminal (electronic whiteboard. 1 a) and theterminal ID “01ba” of the destination terminal (electronic whiteboard 1b). Accordingly, the data exchange unit 51 of the communicationmanagement apparatus 5 receives the start request information and the IPaddress of the request source terminal (electronic whiteboard 1 a) fromwhich the start request information is transmitted.

The storing/reading processing unit 54 updates the terminal managementtable (FIG. 8B) based on the terminal ID “01aa” of the request sourceterminal (electronic whiteboard 1 a) and the terminal ID “01ba” of thedestination terminal (electronic whiteboard 1 b), included in the startrequest information. The storing/reading processing unit 54 updates theterminal management table (FIG. 9B), to change the operating statusesassociated with the terminal IDs “01 aa” and “01ba” to “Online(Communicating)”, based on the terminal ID “01 aa” of the request sourceterminal (electronic whiteboard 1 a) and the terminal ID “01ba” of thedestination terminal (electronic whiteboard 1 b), included in the startrequest information. Although a session between the electronicwhiteboard 1 a (request source terminal) and the electronic whiteboard 1b (destination terminal) is not established, the operating status ofeach terminal is managed as communicating (S33): Accordingly, therequest source terminal (electronic whiteboard 1 a) and the destinationterminal (electronic whiteboard 1 b) have not started a videoconferencebut are in a communicating status. In such case, when a third electronicwhiteboard electronic whiteboard 1 c) tries to make a call with therequest source terminal (electronic whiteboard 1 a) or the destinationterminal (electronic whiteboard 1 b), a notification sound or displayindicating a busy status is output.

Next, a description is given of operation of executing a session forselecting the relay device 3 to be used. The session management unit 55of the communication management apparatus 5 generates a session ID foridentifying a session, to be established between the electronicwhiteboard 1 a and the electronic whiteboard 1 b (S34). In thisembodiment, a description is given of an example case in which thesession ID “se01” is generated.

The session management unit 55 stores the session ID “se01.” generatedat 534, the terminal ID “01aa” of the request source terminal(electronic whiteboard 1 a), and the terminal ID “01ba” of thedestination terminal (electronic whiteboard 1 b) in association witheach other in the session management table (FIG. 10B) (535).

Next, the relay device management unit 56 selects the relay device 3that relays data in the session between the request source terminal(electronic whiteboard 1 a) and the destination terminal (electronicwhiteboard 1 b) (S36). For example, the relay device management unit 56refers to the terminal management table (FIG. 89) to determine the relaydevice IDs of the relay devices 3 each having the operating status“Online” in the relay device management table (FIG. 9C), and selects oneof these relay devices 3 having an IP address closest to the IP addressof the request source terminal (electronic whiteboard 1 a). Thefollowing description is given of an example case where the relay device3 identified by the relay device ID “111a” is selected.

When the relay device selection process at S36 is completed, the dataexchange unit 51 of the communication management apparatus 5 transmitsrelay device selection information to the request source terminal(electronic whiteboard 1 a) (S37-1). The relay device selectioninformation includes the IP address of the relay device 3 selected atS36 and the session ID “se01” generated at S34. Further, the requestsource terminal (electronic whiteboard 1 a) acquires the IP address ofthe communication management apparatus 5, which is the transmissionsource of the relay device selection information.

Similarly, the data exchange unit 51 of the communication managementapparatus 5 transmits the relay device selection information to thedestination terminal (electronic whiteboard 1 b) (S37-2). The relaydevice selection information includes the IP address of the relay device3 selected at S36, the terminal ID “01aa” of the request source terminal(electronic whiteboard 1 a), and the session ID “se01” generated at S34.Thereby, the destination terminal (electronic whiteboard 1 b) acquiresthe IP address of the communication management apparatus 5, which is thetransmission source of the relay device selection information, inexecution of a session with the session ID “se01”.

In response to the process of S37-1, the sharing unit 11 a of therequest source terminal (electronic whiteboard 1 a) transmits receptioncompletion information indicating that the relay device selectioninformation is received at S37-1 to the communication managementapparatus 5 (S38-1). The reception completion information includes thesession ID exchanged in the process of S37-1. Thereby, the communicationmanagement apparatus 5 acknowledges that the transmission of the relaydevice selection information, executed with the specific session ID“se01” has been completed.

In response to the process of S37-2, the destination terminal(electronic whiteboard 1 b) also transmits the reception completioninformation indicating that the relay device selection information hasbeen received through the process of S37-2 to the communicationmanagement apparatus 5 (S38-2). The communication management apparatus 5acknowledges that the transmission of the relay device selectioninformation, executed with the specific session ID “se01”, has beencompleted.

Thus, the electronic whiteboard 1 a and the electronic whiteboard 1 bperform a video conference by exchanging site image data and audio datathrough the relay device 3 selected at S36.

Processing of sharing data to be shared:

Next, with reference to FIGS. 16 to 18, processing to start sharing ofdata between the electronic whiteboard 1 a and the electronic whiteboard1 b using remote communication started by the above-described process isdescribed. FIG. 16 is a flowchart illustrating example processing ofselecting sharing target data, to be shared with other electronicwhiteboard, at the electronic whiteboard, according to the embodiment.Although FIG. 16 illustrates processing performed by the electronicwhiteboard 1 a, similar processing may also be performed by theelectronic whiteboard 1 b that is a communication counterpart of theelectronic whiteboard 1 a.

First, the electronic whiteboard 1 a starts processing of sharing animage of screen with the electronic whiteboard 1 b as a remotecommunication counterpart. (S131). The electronic whiteboard 1 a startsscreen sharing processing, after a session is established between thecommunication terminals 1 a and 1 b. Specifically, the electronicwhiteboard 1 a starts screen sharing processing, for example, inresponse to transmission of information indicating completion ofreception at S38-1 of FIG. 15 as a trigger. In this example, theelectronic whiteboard 1 a may start the screen sharing processing, forexample, when the acceptance unit 12 a receives a user selection via apredetermined selection screen displayed on the display 180.

At a start of the screen sharing processing, the display control unit 14a of the electronic whiteboard 1 a controls the display 180 to display asharing target data selection screen 400 for selecting the sharingtarget data (S132). FIG. 17 is a diagram illustrating an example of asharing target data selection screen displayed at the electronicwhiteboard, according to the embodiment. The sharing target dataselection screen 400 of FIG. 17 includes a sharing target data selectionarea 450 for allowing a user A1 of the electronic whiteboard 1 a toselect data to be shared with the electronic whiteboard 1 b, from amonga plurality of items of screen data for a drawing screen having beengenerated at the electronic whiteboard 1 a. In this example, the sharingtarget data selection area 450 includes selection icons 455 (455A to455C) corresponding to respective drawing screens (screen data ofdrawing screen), and an “OK” button 457 to be pressed to start sharingof data with the electronic whiteboard 1 b.

For example, the display control unit 14 a refers to the drawing screeninformation management table of FIG. 10, to generate the selection icons455 that correspond to a plurality of items of screen data of a drawingscreen generated at the electronic whiteboard 1 a, as described abovereferring to FIG. 11. That is, as described above referring to FIG. 11,the electronic whiteboard 1 a stores, in its local memory, informationon screen data of a drawing screen having been generated at theelectronic whiteboard 1 a in relation to a particular conference. Inthis example, it is assumed that the electronic whiteboard 1 a generatesdrawing screens 200A, 200B, and 200C of FIGS. 12A, 12B, and 12C, inrelation to the conference identified with the se01, before startingsharing of data with the electronic whiteboard 1 b. In such case, thedisplay control unit 14 a displays the selection icons 455A to 455C. Inparticular, the selection icon 455A corresponds to the drawing screen200A illustrated in FIG. 12A, the selection icon 455B corresponds to thedrawing screen 200B illustrated in FIG. 12B, and the selection icon 455Ccorresponds to the drawing screen 200C illustrated in FIG. 12C.

Further, the sharing target data selection area 450 is displayed inreduced size, at a lower side of the sharing target data selectionscreen 400 displayed on the display 180, as illustrated in FIG. 17. Asthe sharing target data selection area 450 is reduced in size, any imageof screen data displayed in the sharing target data selection area 450is also displayed in reduced size. When the screen sharing processingstarts, the display control unit 14 a of the electronic whiteboard 1 aswitches from the drawing screen having been just displayed, to a blankscreen (blank page). In addition, the sharing target data selectionscreen 400 in which the sharing target data selection area 450 isdisplayed in reduced size, is displayed on the display 180, asillustrated in FIG. 17. Any one of the sharing target data selectionscreen 400 and the sharing target data selection area 450 may have anappearance other than the one described above. For example, any of theselection screen 400 and the selection area 450 may be expressed, usingsuch as animation to be easily understood by the user to improve UX(User Experience). In another example, the selection area 450 may bedisplayed in any portion of the selection screen 400.

When the user A1 presses the “OK” button 457 after selecting at leastone of the selection icons 455 in the sharing target data selection area450, the acceptance unit 12 a accepts a selection of screen data to beshared with the electronic whiteboard 1 b, as sharing target data(S133). The acceptance unit 12 a may receive selection of one item ofdata corresponding to one selection icon 455, or may receive selectionof plural items of data respectively corresponding to the plurality ofselection icons 455. With this configuration, the user of the electronicwhiteboard 1 shares only the data he/she wants to share with users ofother electronic whiteboards, from among screen data of drawing screenshaving been already generated at the electronic whiteboard 1 whenstarting a remote conference.

Referring now to FIG. 18, processing of sharing data between theelectronic whiteboard 1 a and the electronic whiteboard 1 b is describedaccording to the embodiment. FIG. 18 is a diagram illustrating anexample operation of sharing data between electronic whiteboards in thecommunication system according to the embodiment. In this example,screen data corresponding to the selection icons 455A to 455C displayedon a selection area 450 a of a sharing target data selection screen 400a (as described above referring to FIG. 17) of the electronic whiteboard1 a are referred to as data A to data C, respectively. Further, screendata corresponding to selection icons 455D to 455F displayed on aselection area 450 b of a sharing target data selection screen 400 hdisplayed on the electronic whiteboard 1 b are referred to as data. D todata. F, respectively.

As illustrated in FIG. 18, at the electronic whiteboard 1 a, data A,data B, and data C are selected as sharing target data from the sharingtarget data selection screen 400 a, as described above referring to FIG.16. The electronic whiteboard 1 a uploads the sharing target data, thatis, the data A, the data B, and the data C, which are selected, to thecommunication management apparatus 5. Then, the counterpart electronicwhiteboard 1 b downloads the data A, the data B, and the data C uploadedby the electronic whiteboard 1 a from the communication managementapparatus 5. For example, the communication management apparatus 5 maycause the electronic whiteboard 1 b to download the data A, the data B,and the data C, or may transmit the data A, the data B, and the data Cto the electronic whiteboard 1 b.

The electronic whiteboard 1 b may store, in its local memory, the dataA, the data B, and the data C that are downloaded at least temporarily.For example, as described above below referring to FIGS. 19 and 20, theelectronic whiteboard 1 b stores information on the downloaded data, inthe drawing screen information management table of FIG. 10.

In this example, it is assumed that the electronic whiteboard 1 b hasalready generated a drawing screen made up of screen data, specifically,the data D, the data E, and the data F, for example, in a substantiallysimilar manner as described above referring to FIG. 11. The acceptanceunit 12 b of the electronic whiteboard 1 b accepts a selection of thedata D and the data E as the sharing target data, in a substantiallysimilar manner as described above referring to FIG. 16. The electronicwhiteboard 1 b uploads the data D and the data E, which are selected, tothe communication management apparatus 5. Then, the electronicwhiteboard 1 a downloads the data D and the data. E uploaded by theelectronic whiteboard 1 b from the communication management apparatus 5.The electronic whiteboard 1 a may store, in its local memory, the data Dand the data E that are downloaded at least temporarily. For example, asdescribed below referring to FIGS. 19 and 20, the electronic whiteboard1 a stores information on the downloaded data, in the drawing screeninformation management table of FIG. 10.

With this configuration, the communication system allows sharing ofscreen data corresponding to drawing screen having been alreadygenerated at each electronic whiteboard (communication terminal) at thestart of the remote conference, between the electronic whiteboard 1 aand the electronic whiteboard 1 b. Further, the communication systemallows selection of data to be shared with other party, at each of theelectronic whiteboard 1 a and the electronic whiteboard 1 b, such thatonly the data that the user wants to share in the remote conference isshared.

Sharing of Data between Electronic Whiteboards:

Referring to FIGS. 19 to 22, processing of sharing data between aplurality of electronic whiteboards 1 is described according to theembodiment. FIGS. 19 to 22 are sequence diagrams illustrating an exampleoperation of sharing data between electronic whiteboards in thecommunication system according to the embodiment. In the presentembodiment, the electronic whiteboard 1 a and the electronic whiteboard1 b share data, such as the background image data and the stroke data.Here, a case where the background image and the stroke image displayedon the electronic whiteboard 1 a are also displayed on the electronicwhiteboard 1 b is described. The processing is performed in asubstantially similar manner for a case where the background image andthe stroke image displayed on the electronic whiteboard 1 b aredisplayed on the electronic whiteboard 1 a.

The drawing screen management unit 57 of the communication managementapparatus 5 receives the reception completion information from eachelectronic whiteboard 1 through S38-1 and S38-2 of FIG. 15. Further, thescreen data to be initially shared is selected as described abovereferring to FIG. 16. The processing of FIGS. 19 and 20 are thusperformed to share data having been selected through processing of FIG.16, such that at least one of the selected data is initially displayedat each electronic whiteboard.

The drawing screen management unit 57 stores, in the drawing screeninformation management DB 5006 (FIG. 10), conference information on theremote conference to be started (S51), Specifically, the drawing screenmanagement unit 57 stores the session ID included in the receivedreception completion information as the conference ID. The drawingscreen management unit 57 assigns a gid corresponding to the remoteconference to be started.

Next, the sharing unit 11 a of the electronic whiteboard 1 a transmits apage information addition request that requests addition of pageinformation to the communication management apparatus 5 (S52). This pageinformation addition request includes a page ID for identifying a pagefor which addition is requested, and information (parent) foridentifying a conference being conducted at the electronic whiteboard 1a. The data exchange unit 51 of the communication management apparatus 5receives the page information addition request from the electronicwhiteboard 1 a.

Next, the drawing screen management unit 57 causes the drawing screeninformation management DB 5006 (FIG. 11) to store various informationreceived at S52 as page information (S53). The drawing screen managementunit 57 also assigns a gid corresponding to the page (page data) to bestored in the drawing screen information management DB 5006.

The data exchange unit 51 transmits, to the electronic whiteboard 1 a, apage information addition notification indicating that the pageinformation is added to the drawing screen information management DB5006 (S54). This page information addition notification includes a pageID for identifying the added page information (parent) for identifying aconference being conducted at the electronic whiteboard 1 a, andinformation on gid numbered by the drawing screen management unit 57.Accordingly, the sharing unit 11 a of the electronic whiteboard 1 areceives the page information addition notification transmitted from thecommunication management apparatus 5, Further, the data exchange unit 51transmits a page information addition notification to the electronicwhiteboard 1 b as a counterpart terminal (S55). The information includedin the page information addition notification is the same as theinformation transmitted to the electronic whiteboard 1 a at S54.Accordingly, the sharing unit 11 b of the electronic whiteboard 1 breceives the page information addition notification transmitted from thecommunication management apparatus 5.

Subsequently, the sharing unit 11 a of the electronic whiteboard 1 atransmits a conference information update request indicating update ofthe conference information to the communication management apparatus 5(S56). The conference information update request includes the gid of theconference information requested to be updated, the conference ID foridentifying the conference being conducted at the electronic whiteboard1 a, the information (children) indicating the page generated in theconference, and information (current page) the page currently displayedon the electronic whiteboard 1 a. The data exchange unit 51 of thecommunication management apparatus 5 receives the conference informationupdate request from the electronic whiteboard 1 a.

Next, the drawing screen management unit 57 updates the conferenceinformation stored in the drawing screen information management DB 5006(FIG. 11) based on various information received at S56 (S57). In thiscase, the drawing screen management unit 57 searches the drawing screeninformation management table to update the information (body) associatedwith the conference ID received at the data exchange unit 51. Inaddition, the drawing screen management unit 57 updates the gid of theconference information received at S56.

The data exchange unit 51 transmits a conference information updatenotification indicating that the conference information has been updatedto the electronic whiteboard 1 a (S58). The conference informationupdate notification includes the gid updated at S57, the conference IDfor identifying the conference being conducted at the electronicwhiteboard the information (children) indicating the page generated inthe conference, and the information (current page) on a page currentlydisplayed on the electronic whiteboard 1 a. Accordingly, the sharingunit 11 a of the electronic whiteboard 1 a receives the conferenceinformation update notification transmitted from the communicationmanagement apparatus 5. Further, the data exchange unit 51 transmits aconference information update notification to the electronic whiteboard1 b as a counterpart terminal (S59). The information included in thisconference information update notification is the same as theinformation transmitted to the electronic whiteboard 1 a at S58.Accordingly, the sharing unit 11 b of the electronic whiteboard 1 breceives the conference information update notification transmitted fromthe communication management apparatus 5.

The sharing unit 11 a of the electronic whiteboard 1 a transmits anupload request of the background image data to the image storage device7 (S60). In this case, the data exchange unit 51 transmits thebackground image data to, for example, a predetermined URL (for example,“http://xxx.jp/upload”) for upload. Thereby, the data exchange unit 71of the image storage device 7 receives the upload request from theelectronic whiteboard 1 a. The storing/reading processing unit 79 of theimage storage device 7 stores the background image data received at S60in the storage unit 7000 (S61). Further, the generation unit 73generates a URL indicating the storage location of the background imagedata stored at S61 (S62). The URL is an example of storage locationinformation. In another example, the storage location informationincludes a URI. The data exchange unit 71 transmits an upload completionnotification indicating that uploading of the background image data iscompleted to the electronic whiteboard 1 a (S63). This upload completionnotification includes the URL generated at S62. Accordingly, the sharingunit 11 a of the electronic whiteboard 1 a receives the uploadcompletion notification transmitted from the image storage device 7,Referring to FIGS. 20 and 21, processing to be performed after thebackground image data is uploaded from the electronic whiteboard 1 a tothe image storage device 7 is described according to the embodimentFirst, referring to FIG. 20, processing to be performed when theelectronic whiteboard 1 a has transmitted the page information additionrequest at S52 is described as an example.

As illustrated in FIG. 20, the sharing unit 11 a of the electronicwhiteboard 1 a transmits, to the communication management apparatus 5, apage information update request requesting update of page information(S71). The page information update request includes the page IL) foridentifying the page, the information (parent) for identifying aconference being conducted at the electronic whiteboard 1 a, the gid ofthe page received at S54, and the URL information received at S63. Thedata exchange unit 51 of the communication management apparatus 5receives the page information update request from the electronicwhiteboard 1 a.

Next, the drawing screen management unit 57 updates the page informationstored in the drawing screen information management DB 5006 (FIG. 11)based on various information received at S71 (S72). Specifically, thedrawing screen management unit 57 searches the drawing screeninformation management table to update the information (body) associatedwith the page ID received at S71. In addition, the drawing screenmanagement unit 57 updates the gid of the page information received atS71.

The data exchange unit 51 of the communication management apparatus 5transmits a page information update notification indicating that thepage information has been updated to the electronic whiteboard 1 a(S73). The page information update notification includes the page ID foridentifying the page, the information (parent) for identifying aconference being conducted at the electronic whiteboard 1 a, the gid ofthe page updated at S72, and the URL information of the background imagedata. Accordingly, the sharing unit 11 a of the electronic whiteboard 1a receives the page information addition notification transmitted fromthe communication management apparatus 5. Further, the data exchangeunit 51 of the communication management apparatus 5 transmits a pageinformation update notification to the electronic whiteboard 1 b as acounterpart terminal (S74). The information included in the pageinformation update notification is the same as the informationtransmitted to the electronic whiteboard 1 a at S73. Accordingly, thesharing unit 11 b of the electronic whiteboard 1 b receives the pageinformation update notification transmitted from the communicationmanagement apparatus 5.

The sharing unit 11 b of the electronic whiteboard 1 b transmits adownload request that requests downloading of the background image data,to the URL received at S74, which indicates the storage location at theimage storage device 7 (S75). Thereby, the data exchange unit 71 of theimage storage device 7 receives the download request from the electronicwhiteboard 1 c.

Next, the storing/reading processing unit 79 of the image storage device7 reads the requested background image data from the storage unit 7000based on the URL indicated by the download request received at the dataexchange unit 71 (S76). The data exchange unit 71 transmits therequested background image data to the electronic whiteboard 1 b as therequest source terminal (S77). Thereby, the sharing unit 11 b of theelectronic whiteboard 1 b downloads (receives) the background imagedata. The display control unit 14 b of the electronic whiteboard 1 bcontrols the display 180 to display the background image based on thebackground image data downloaded (received) at the sharing unit 11 b(S78),

Next, referring to FIG. 21, processing to be performed when theelectronic whiteboard 1 a has not transmitted the page informationaddition request at S52 to the communication management apparatus 5 isdescribed as an example.

As illustrated in FIG. 21, the sharing unit 11 a of the electronicwhiteboard 1 a transmits, to the communication management apparatus 5, apage information addition request requesting addition of pageinformation (S81). This page information addition request includes apage ID for identifying the page for which addition is requested,information (parent) for identifying a conference being conducted at theelectronic whiteboard 1 a, and information on the URL of the backgroundimage data received at S63. The data exchange unit 51 of thecommunication management apparatus 5 receives the page informationaddition request from the electronic whiteboard 1 a.

Next, the drawing screen management unit 57 causes the drawing screeninformation management DB 5006 (FIG. 11) to store various informationreceived at S81 as page information (S82). The drawing screen managementunit 57 also assigns a gid corresponding to the page (page data) to bestored in the drawing screen information management DB 5006.

The data exchange unit 51 transmits, to the electronic whiteboard 1 a, apage information addition notification indicating that the pageinformation is added to the drawing screen information management DB5006 (S83). This page information addition notification includes a pageID for identifying the added page, information (parent) for identifyinga conference being conducted at the electronic whiteboard 1 a,information on gid numbered by the drawing screen management unit 57,and URL information of the background image data. Accordingly, thesharing unit 11 a of the electronic whiteboard 1 a receives the pageinformation addition notification transmitted from the communicationmanagement apparatus 5. Further, the data exchange unit 51 transmits apage information addition notification to the electronic whiteboard 1 bas a counterpart terminal (S84). The information included in the pageinformation addition notification is the same as the informationtransmitted to the electronic whiteboard 1 a at S83. Accordingly, thesharing unit 11 b of the electronic whiteboard 1 b receives the pageinformation addition notification transmitted from the communicationmanagement apparatus 5.

Subsequently, the sharing unit 11 a of the electronic whiteboard 1 atransmits a conference information update request indicating update ofthe conference information to the communication management apparatus 5(S85). The conference information update request includes the gid of theconference information requested to be updated, the conference ID foridentifying the conference being conducted at the electronic whiteboard1 a, the information (children) indicating the page generated in theconference, and information (current page) on the page currentlydisplayed on the electronic whiteboard 1 a. The data exchange unit 51 ofthe communication management apparatus 5 receives the conferenceinformation update request from the electronic whiteboard 1 a.

Next, the drawing screen management unit 57 updates the conferenceinformation stored in the drawing screen information management DB 5006(FIG. 11) based on various information received at S85 (S86). In thiscase, the drawing screen management unit 57 searches the drawing screeninformation management table to update the information (body) associatedwith the conference ID received at the data exchange unit 51. Inaddition, the drawing screen management unit 57 updates the gid of theconference information received at S85.

The data exchange unit 51 transmits a conference information updatenotification indicating that the conference information has been updatedto the electronic whiteboard 1 a (S87). The conference informationupdate notification includes the gid updated at S56, the conference IDfor identifying the conference being conducted at the electronicwhiteboard 1 a, the information (children) indicating the page generatedin the conference, and the information (current page) on a pagecurrently displayed on the electronic whiteboard 1 a. Accordingly, thesharing unit 11 a of the electronic whiteboard 1 a receives theconference information update notification transmitted from thecommunication management apparatus 5, Further, the data exchange unit 51transmits a conference information update notification to the electronicwhiteboard 1 b as a counterpart terminal (S88). The information includedin this conference information update notification is the same as theinformation transmitted to the electronic whiteboard 1 a at S87.Accordingly, the sharing unit 11 b of the electronic whiteboard 1 breceives the conference information update notification transmitted fromthe communication management apparatus 5. Processing from S89 to S92 areperformed in the same or substantially the same manner as S75 to S78described above with reference to FIG. 20, and thus redundantdescriptions thereof are omitted below.

Referring to FIG. 22, processing of sharing data generated by theelectronic whiteboard 1 a with the electronic whiteboard 1 b isdescribed according to the embodiment. The sharing unit 11 a of theelectronic whiteboard 1 a transmits stroke data generated by the imageprocessing unit 16 a to the communication management apparatus 5 (S101).Thereby, the data exchange unit 51 of the communication managementapparatus 5 receives the stroke data transmitted from the electronicwhiteboard 1 a. The drawing screen management unit 57 stores the strokedata received at S101 in the drawing screen information management DB5006 (FIG. 11) (S102). In this case, as illustrated in FIG. 11, thedrawing screen management unit 57 stores, in the stroke data informationmanagement table, items of the stroke data received by the data exchangeunit 51 a in the order of occurrence (sequence order) in associationwith the conference ID (the session ID) of a session with which theremote conference is conducted. Further, the drawing screen managementunit 57 assigns a specific number to the gid, associated with the strokedata received at S102.

Next, the data exchange unit 51 transmits the stroke data stored at S102and the gid having the number assigned by the drawing screen managementunit 57, to the electronic whiteboard 1 a (S103). Accordingly, theelectronic whiteboard 1 a receives the stroke data and the gidtransmitted from the communication management apparatus 5. That is, theelectronic whiteboard 1 a is informed of the accepted stroke data andthe numbered gid.

The data exchange unit 51 transmits the stroke data and the gid to theelectronic whiteboard 1 b, which is the counterpart terminal (S104).Accordingly, the sharing unit 11 b of the electronic whiteboard 1 breceives the stroke data and the gid transmitted from the communicationmanagement apparatus 5. Then, the image processing unit 16 b of theelectronic whiteboard 1 b generates a stroke image based on the strokedata received at the sharing unit 11 b (S105). Then, the display controlunit 14 b controls the display 180 of the electronic whiteboard 1 b todisplay the stroke image generated at S105 (S106). Accordingly, thecommunication system allows sharing of the stroke image drawn on theelectronic whiteboard 1 a with the electronic whiteboard 1 b.

Accordingly, the electronic whiteboard 1 a and the electronic whiteboard1 b can share the stroke image and the background image displayed on thedisplay 180. The background image data of the background image displayedon the electronic whiteboard 1 a is uploaded to the image storage device7, and is then downloaded to the electronic whiteboard 1 b. Further,stroke data of strokes drawn on the electronic whiteboard 1 a is sharedwith the electronic whiteboard 1 b via the communication managementapparatus 5. The background image data sharing process describedreferring to FIGS. 19 to 21 and the stroke data sharing processdescribed referring to S101 to S106 of FIG. 22 may be performed in anyorder other than the above-described order, or may be performedconcurrently.

In this manner, through repeating processing illustrated in FIGS. 19 to20, the electronic whiteboard 1 a is able to share screen data to beshared, which is selected using the sharing target selection screen 400illustrated in FIG. 17, with the electronic whiteboard 1 b, at a startof processing to share data. Further, when a plurality of items ofscreen data are selected as sharing target data, the electronicwhiteboard 1 a preferentially displays screen data corresponding to thedrawing screen displayed immediately before executing the screen sharingprocessing. The screen data corresponding to the drawing screendisplayed immediately before executing the screen sharing processing,corresponds to the screen data of “current page” included in theconference information. Accordingly, the electronic whiteboard 1 a canpreferentially display the drawing screen corresponding to the topichaving been discussed just before sharing of data starts, with theelectronic whiteboard 1 b, such that the sharing of data can be smoothlystarted.

Processing of Selecting Top Screen:

Next, referring to FIGS. 23 to 25, processing of selecting a top screento be initially displayed on each electronic whiteboard 1 in the remoteconference, from among data shared between the electronic whiteboard 1 aand the electronic whiteboard 1 b, is described according to theembodiment. FIG. 23 is a flowchart illustrating example processing ofselecting a top screen at the electronic whiteboard. In the followingexample, it is assumed that each of the data (data A to data E)illustrated in FIG. 18 is shared between the electronic whiteboard 1 aand the electronic whiteboard 1 b. Although FIG. 23 illustratesprocessing to be performed by the electronic whiteboard 1 a, the sameprocessing may be performed by the electronic whiteboard 1 b as acommunication counterpart.

First, the display control unit 14 a of the electronic whiteboard 1 acauses the display 180 to display a top screen candidate selectionscreen 600 for selecting a top screen, which is a drawing screen to befirstly displayed (S151). FIG. 24 is a diagram illustrating an exampleof a top screen candidate selection screen displayed at the electronicwhiteboard, according to the embodiment. The top screen candidateselection screen 600 illustrated in FIG. 24 includes a plurality ofselection icons 610 (610A to 610E), corresponding to sharing target data(data A to data C) selected using the sharing target data selectionscreen 400 in FIG. 17, and screen data (data D and data E) received atthe sharing unit 11 a from the electronic whiteboard 1 b. Specifically,the selection icons 610A to 610C correspond to the sharing target data(data A to data C) selected using the sharing target data selectionscreen 400, and the selection icons 610D and 610E are the screen data(data D and data. E) transmitted from the electronic whiteboard 1 b. Thetop screen candidate selection screen 600 further includes an operationright change button 630 to be pressed to change a user with an operationright for selecting a top screen, and an “OK” button 650 to be pressedto determine the top screen. The operation right indicates whether theuser has a right, or authority, to select a top screen.

The operation right for selecting the top screen can be changed by theuser selecting the operation right change button 630. At the electronicwhiteboard 1 of the user having the operation right. “operation rightYES” indicating that the user has the operation right is displayed. Atthe electronic whiteboard 1 of the user without the operation right,“operation right NO” indicating that the user has no operation right isdisplayed. As a default selling, the operation right is given to arequest source terminal (for example, the electronic whiteboard 1 a)that has requested sharing of data with other electronic whiteboard 1 orstarting of remote communication (remote conference), or the useroperating the request source terminal. As described above, thecommunication system restricts an electronic whiteboard (communicationterminal) that can have the operation right to select the top screen, soas to avoid any conflict that may be caused by allowing selection of atop screen from different electronic whiteboards. The top screencandidate selection screen 600 may have an appearance other than the onedescribed above. For example, any part of the top screen candidateselection screen 600 may be expressed, using such as animation to beeasily understood by the user to improve UX (User Experience).

Next, the determination unit 15 a determines whether or not the user atthe electronic whiteboard 1 has the operation right for selecting thetop screen (S152). When the determination unit 15 a determines that theuser has the operation right (YES at S152), the operation proceeds toS153. When the determination unit 15 a determines that the user does nothave the operation right (NO at S152), the operation proceeds to S154.In the example of FIG. 24, the electronic whiteboard 1 a, which is arequest source terminal, is determined to have the operation right.

Next, when the user A1 presses the “OK” button 650 after selecting atleast one of the selection icons 610 included in the top screencandidate selection screen 600, the acceptance unit 12 a receives theselection of the top screen candidate (S153). In the example of FIG. 24,the selection icon 610C is selected by the user A1, and the acceptanceunit 12 a receives the selection of the drawing screen 200C as a topscreen candidate to be displayed.

Then, the display control unit 14 a controls the display 180 to displaya drawing screen corresponding to the top screen candidate selected atS153, as a top screen 250. FIG. 25 is a diagram illustrating an exampleof a top screen displayed at the electronic whiteboard, according to theembodiment. The top screen 250 illustrated in FIG. 25 is the same as thedrawing screen 200C corresponding to the selection icon 610C selectedfrom the top screen candidate selection screen 600 illustrated in FIG.24. This top screen 250 is also shared and displayed at the electronicwhiteboard 1 b.

As described above, when a plurality of items of screen data is sharedwith the electronic whiteboard 1 b, the electronic whiteboard 1 a allowsthe user A1 to select the screen data of the top screen 250, which is adrawing screen to be initially displayed, from among a plurality ofitems of screen data that are shared. Accordingly, the user is able tostart a remote conference smoothly using a desired drawing screen.

As described above, the electronic whiteboard 1 a according to one ormore embodiments is an example of communication terminal that sharesdata with the communication terminal 1 b (an example of othercommunication terminal). The electronic whiteboard 1 a receives aselection of sharing target data, which is data to be shared with theelectronic whiteboard 1 b, from among one or more items of screen dataof a drawing screen (an example of a display screen) having beengenerated at the electronic whiteboard 1 a. The electronic whiteboard 1a shares the screen data, selected as the sharing target data, with theelectronic whiteboard 1 b. With this configuration, the electronicwhiteboard 1 a selects data according to an instruction from the userA1, from among one or more items of screen data having been generatedbefore starting sharing of data with the electronic whiteboard 1 b, toshare only the selected data with the electronic whiteboard 1 b todisplay as a display screen. This facilitates a smooth start of theremote conference.

According to one or more embodiments, the electronic whiteboard 1 a (anexample of a communication terminal) receives sharing target data of theother communication terminal, that is, screen data selected from amongone or more items of screen data generated at the electronic whiteboard1 b (an example of other communication terminal), and causes the display180 (an example of displaying unit) to display the top screen candidateselection screen 600 including the sharing target data of the othercommunication terminal and the sharing target data of the communicationterminal. The electronic whiteboard 1 a receives a selection of screendata of a drawing screen (an example of display screen) to be sharedwith the electronic whiteboard 1 b (an example of other communicationterminal) for display at the display 180, from among screen data in thetop screen candidate selection screen 600. The electronic whiteboard 1 acauses the display 180 to display a drawing screen made up of theselected screen data as a top screen 250. As described above, when aplurality of items of screen data is shared with the electronicwhiteboard 1 b, the electronic whiteboard 1 a allows the user A1 toselect the screen data of the top screen 250, which is a display screento be firstly displayed, from among shared screen data. Accordingly, theuser is able to start a remote conference smoothly using a desireddisplay screen.

Further, according to one example, the operation right for selecting thetop screen 250 is given to a request source terminal that has requestedto start sharing of data. For example, the electronic whiteboard 1 a, asthe request source terminal, receives a selection of screen data, fromamong data illustrated in the top screen candidate selection screen 600,to be displayed as the top screen 250. By restricting an electronicwhiteboard (communication terminal) that can have the operation right toselect the top screen 250, the electronic whiteboard 1 a can avoid anyconflict that may be otherwise caused by allowing the electronicwhiteboard 1 b to select a top screen.

According to one or more embodiments, when starting sharing of data withthe electronic whiteboard 1 b (an example of other electronicwhiteboard), the electronic whiteboard 1 a (an example of acommunication terminal) controls the display 180 (an example of adisplaying unit) to display a sharing target data selection screen 400that displays a plurality of items of screen data of a drawing screen(an example of a display screen) having been generated at the electronicwhiteboard 1 a. The electronic whiteboard 1 a further receives aselection of sharing target data, from among the plurality of items ofscreen data being displayed in the sharing target data selection screen400. With this configuration, the user of the electronic whiteboard 1 ashares only the data he/she wants to share with users of otherelectronic whiteboards, from among screen data of drawing screens havingbeen already generated at the electronic whiteboard 1 a when starting aremote conference.

Further, according to one or more embodiments, the electronic whiteboard1 a (an example of a communication terminal) preferentially sharesscreen data that is used for displaying a drawing screen (an example ofa display screen), currently displayed on the display 180 (an example ofa displaying unit), from among screen data as sharing target data thatis received. Accordingly, the electronic whiteboard 1 a canpreferentially share the drawing screen corresponding to the topichaving been discussed just before sharing of data is started, with theelectronic whiteboard 1 b, such that the remote conference can besmoothly started.

Each of the functions of the described embodiments may be implemented byone or more processing circuits or circuitry. Processing circuitryincludes a programmed processor, as a processor includes circuitry. Aprocessing circuit also includes devices such as an application specificintegrated circuit (ASIC), digital signal processor (DSP), and fieldprogrammable gate array (FPGA), and conventional circuit componentsarranged to perform the recited functions.

Further, various tables of any one of the above-described embodimentsmay be generated by machine learning. Further, data of associated itemscan be classified, such that use of tables can be optional. In thepresent disclosure, machine learning is a technique that enables acomputer to acquire human-like learning ability. Machine learning refersto a technology in which a computer autonomously generates an algorithmrequired for determination such as data identification from learningdata loaded in advance, and applies the generated algorithm to new datato make a prediction. Any suitable learning method is applied formachine learning, for example, any one of supervised learning,unsupervised learning, semi-supervised learning, reinforcement learning,and deep learning, or a combination of two or more those learning.

Although the communication terminal, the communication system, the datasharing method, and the program according to embodiments of the presentinvention are described above, the above-described embodiments areillustrative and do not limit the present invention. Thus, numerousadditional modifications and variations are possible in light of theabove teachings. For example, elements and/or features of differentillustrative embodiments may be combined with each other and/orsubstituted for each other within the scope of the present invention.Any one of the above-described operations may be performed in variousother ways, for example, in an order different from the one describedabove.

1. A communication terminal comprising circuitry configured to: receive selection of screen data, from among one or more items of screen data, as sharing target data to be shared with other communication terminal, each screen data to be used for generating a display screen and having been generated at the communication terminal; and share the sharing target data with the other communication terminal.
 2. The communication terminal of claim 1, wherein the circuitry is further configured to transmit the sharing target data to the other communication terminal, via a server that manages data to be shared with the other communication terminal.
 3. The communication terminal of claim 1, wherein the circuitry is configured to receive sharing target data of the other communication terminal, the sharing target data of the other communication terminal being selected from among one or more items of screen data each screen data to be used for generating a display screen and having been generated at the other communication terminal, and control a display to display a display screen generated based on particular screen data, the particular screen data being one of the sharing target data of the communication terminal and the sharing target data of the other communication terminal.
 4. The communication terminal of claim 3, wherein the circuitry is configured to receive selection of the particular screen data, from among the sharing target data of the communication terminal and the sharing target data of the other communication terminal, and control the display to display the display screen based on the particular screen data, as a top screen to be initially displayed at a start of sharing of data with the other communication terminal.
 5. The communication terminal of claim 4, wherein the circuitry is configured to control the display to display a selection screen including the sharing target data of the communication terminal and the sharing target data of the other communication terminal, for allowing a user to select the particular screen data as a candidate of the top screen.
 6. The communication terminal of claim 5, wherein the circuitry is configured to determine whether the communication terminal or the user operating the communication terminal has a right to select the top screen, and receive the selection of the particular screen data as the top screen based on a determination that the communication terminal or the user operating the communication terminal has a right to select the top screen.
 7. The communication terminal of claim 6, wherein the right to select the top screen is assigned to the communication terminal or the user operating the communication terminal, in a case that the communication terminal requests to start sharing of data with the other communication terminal.
 8. The communication terminal of claim 1, wherein the circuitry is configured to at a start of sharing of data with the other communication terminal, control the display to display a sharing target data selection screen that displays the one or more items of screen data having been generated at the communication terminal, and receives the selection of screen data from the one or more items of screen data via the sharing target data selection screen.
 9. The communication terminal of claim 8, wherein the sharing target data selection screen displays a reduced-size image of a display screen based on the screen data.
 10. The communication terminal of claim 1, wherein, when a plurality of items of screen data is selected as the sharing target data of the communication terminal, the circuitry is configured to share with priority, the screen data used for generating a display screen being currently displayed at the display of the communication terminal, such that the screen data of the currently-displayed display screen is initially displayed at the other communication terminal.
 11. The communication terminal of claim 1, wherein the screen data includes stroke data used for displaying a stroke image contained in the display screen.
 12. The communication terminal of claim 1, wherein the screen data includes background image data of a background image contained in the display screen.
 13. A communication system comprising: a first communication terminal; and a second communication terminal configured to share data with the first communication terminal, the first communication terminal including first circuitry configured to: receive selection of screen data, from among one or more items of screen data, as first sharing target data to be shared with the second communication terminal, each screen data to be used for generating a display screen and having been generated at the first communication terminal; and share the first sharing target data with the second communication terminal, the second communication terminal including second circuitry configured to: receive selection of screen data, from among one or more items of screen data, as second sharing target data to be shared with the first communication terminal, each screen data to be used for generating a display screen and having been generated at the second communication terminal; and share the second sharing target data with the first communication terminal.
 14. The communication system of claim 13, wherein the first circuitry and the second circuitry are each configured to control a corresponding display to display a display screen generated based on particular screen data, the particular screen data being one of the sharing target data of the first communication terminal and the sharing target data of the second communication terminal.
 15. A method of sharing data between a first communication terminal and a second communication terminal, the method comprising: at the first communication terminal, receiving selection of screen data, from among one or more items of screen data, as sharing target data to be shared with a second communication terminal, each screen data to be used for generating a display screen and having been generated at the first communication terminal; and sharing the sharing target data of the first communication terminal with the second communication terminal.
 16. The method of claim 15, further comprising: at the second communication terminal, receiving selection of screen data, from among one or more items of screen data, as sharing target data to be shared with the first communication terminal, each screen data to be used for generating a display screen and having been generated at the second communication terminal; and sharing the sharing target data of the second communication terminal with the first communication terminal. 